Troubleshooting 2 Stroke Ignition Problems

Author: Stuart Buckingham   Date Posted:30 March 2017 

The most common thing I get asked over the phone to assist with is diagnosing outboard ignition problems. Whilst I am always happy to try and help in diagnosis, it can be very hard to do so over the phone. Apart from having the right tools to assist in diagnosis, a basic understanding of how a two stroke ignition system works is fundamental. The following is a list of what makes up an ignition system from start to finish.

1. Battery

Your boat battery is where it all starts. Outboards require higher cold cranking amps than many other engines and therefore a dedicated marine battery with the correct cranking capacity for your outboard is a must. Without the correct voltage, your outboards starter motor may not be able to crank the flywheel fast enough to activate your ignition system.

2. Ignition Switch

To activate your engine and crank it over you need a switch. Every electric start outboard has an ignition switch and it will open and shut the starter solenoid. It also turns the engine off by shorting the CDI unit (power pack or switchbox) to ground. A faulty ignition switch can cause all sorts of problems with your ignition system and is more often than not overlooked.

3. Starter Solenoid

This is effectively a gate. The ignition switch sends a signal to the solenoid when you turn your key allowing it to open; this allows voltage from your battery to pass through it to the starter motor. If you're turning your key and the starter motor isn't cranking then you may have a faulty solenoid.

4. Flywheel

When your starter motor is turning over it is spinning your flywheel to create voltage for your ignition system and battery charging system. On the inside of the flywheel are magnets that spin around a stator at high speed to create AC voltage. The flywheel also spins around the trigger (or timer base) to determine your engines firing sequence or timing. Broken or loose magnets on your flywheel will cause ignition issues so they are definitely worth checking.

5. Stator

Your stator creates voltage for two reasons. To send voltage to your CDI unit (power pack or switchbox) to run your engine and to send voltage to your rectifier/regulator that will charge your battery. Engines with no spark or intermittent spark on one bank can be caused by a faulty stator.

6. Trigger

Nestled in with the stator under the flywheel is the trigger (or timer base). Probably the most overlooked part of the ignition system the trigger sends a signal to the CDI unit (power pack or switchbox) and tells it when to release voltage to the coil. A faulty trigger will result in no or intermittent spark and is often misdiagnosed as a fault with the power pack. Additionally, a faulty trigger shorting to ground will damage a power-pack so be careful if fitting a new power pack.

7. CDI Unit

Depending on your outboard brand these units will go by different names but, they will all have the same function and that is to store voltage from the stator and release it to your ignition coil when the trigger tells it to. Often a faulty CDI unit will see intermittent or no spark on cylinders and may only breakdown when your engine warms up.

8. Ignition Coil

Receiving voltage from the CDI unit the coil will amplify voltage and shoot it through to the spark plug. Faulty or damaged coils will have weak or no output. We see a lot of coil failures where customers are using a spark plug that is not recommended by the manufacturer.

9. Spark Plug

This is the last component in your ignition system. The spark plug receives voltage from your ignition coil and creates a small electrical spark within your engines combustion chamber igniting your engine's fuel and creating the explosion that drives the piston to spin the crankshaft and the flywheel where the ignition process begins over and over again. Spark plugs can foul up with oil and carbon on two stroke engines resulting in poor spark. They are by far the easiest part to check first.

10. Rectifier/Regulator

Fitting in somewhere between all this is your engines rectifier/regulator. It is always working and its job is to replace the voltage in your battery that you've lost due to engine cranking, using electric tilt and trim, running fish finders, lights or other accessories on your boat. It converts the AC voltage to DC voltage and regulates how much voltage it is putting into your battery. In a lot of cases, a rectifier/regulator also sends the signal to your RPM gauge (tacho) telling you what revs your engine is doing. Sometimes the first sign of a faulty rectifier/regulator is when your RPM gauge stops working and this is very common with older Evinrude/Johnson outboards.

 

There are variances here and there, but I’ve gone for the most common and basic approach on this occasion. I hope the above has given you some insight into how your outboard ignition system works. Keep these points in mind if you ever have a potential ignition problem and hopefully, it will make a diagnosis that bit easier.  But remember, in order to diagnose ignition problems properly a Digital Multimeter with a Direct Voltage Adaptor (DVA) is a must have tool for accurate diagnosis. Another very helpful piece of material is the CDI Electronics Troubleshooting Guide, click here for pages of helpful information on almost every two stroke engine.

To shop our range of ignition parts, click here.

Comments (225)

Evinrude 70hp 2 stroke 1970's model.

By: on 18 August 2024
Hi, my partner and I bought a 1970s ran obout with a 70hp stroke engine. Worked well for a couple of months then had issue after issue. Almost every part in the engine has been replaced with new or second hand parts. Everything listed here has been fixed: Fuel lines, battery, carburettors cleaned and replaced 3 times, spark plugs, stator, starter motor, pumps, coils, electrical cables, fuel pump, tilt motor, plus its been tuned and timed 3 times also. And she still won't run properly. When muffs are on she rans, sound good, revs but when put in the water she stalls, has no power, bogs down at full throttle still unable to get on a plane or go faster than 10knots. I've spent so much money (3000 in parts and labour) trying to fix it I could have bought a refurbished second hand engine. Feeling frustrated. Do I keep trying or call it quits

Outboard Spares Response
Good Day, There are a couple of things I would look at. 1) Power pack. These are prone to failing. 2) Leaking base gasket. As your engine is running ok on the flushing muffs but not ok in the water, it could be that the exhaust back-pressue when it is in the water is causing some exhaust gas to push up into the cowl and choke the outboard. I would therefore try running the outboard in the water with the cowl off. If it runs ok, I would replace the base gasket. 3) Worn Crankcase. When the crankcase is worn around the crankshaft, gases will leak between cylinders. Sometimes this will cause the engine to stall. Check the first 2 points I've listed and go from there. Cheers Stuart

Johnson 60hp -86

By: on 28 July 2024
Hi, I've got a ignition issue. My engine runs on 2 out of 3 cylinders, if i remove ignition cap on cylinder one it runs on two and three, and if remove it from cylinder three it runs on two and one. I've got spark on all 3 plugs when checking. Is it a trigger problem?

Outboard Spares Response
HI, I would get a spark tester and check for spark on each plug. If you find it is not running on a particular cylinder I would check voltage between the powerpack and timer base (trigger). I would suggest one of the 2 have a problem. If so, I would recommend replacing both components at the same time. Good Luck.

2 stroke 150 black max 1982

By: on 10 July 2024
motor ran but had a miss in motor when revved up.. found corrosion in two coils and hard dry plug wires new wires and coils motor will not start ..checked spark all plugs have spark still no start not even with a shot of starter fluid nice white spark all plugs 115 lbs. or better all cylinders help please

Outboard Spares Response
Hi, You might need to check the firing order. It might not be correct after changing the coils which will be why it's not starting. Cheers

2000 25hp mercury tracker 2 stroke

By: on 29 June 2024
Runs great 30 minutes or so then struggles to reach plane again has limited power went thru entire fuel system replaced power packs rebuilt carburetor and fuel pump thinking maybe the trigger or the stator?? Also have replaced thermostat so don’t think motor is over heating

Outboard Spares Response
Hi there, You are most likely on the right path of a stator, trigger or switch box. Try doing an ohms test and checking the results to oem specs. Try again after it plays up and compare the results. If not to oem specs then replace the component Regards,

2000 25hp mercury tracker 2 stroke

By: on 29 June 2024
Runs great 30 minutes or so then struggles to reach plane again has limited power went thru entire fuel system replaced power packs rebuilt carburetor and fuel pump thinking maybe the trigger or the stator?? Also have replaced thermostat so don’t think motor is over heating

Outboard Spares Response
HI, I would try priming the primer bulb when the issue starts to see if it is a fuel delivery issue. It could be a fuel tank breather or tank pick up problem, not neccessarily the engine itself. These engines have 1 x switch-box and 2 x coils. Was it therefore the coils that were replaced and not the switchbox? The switchbox on these motors are notorious for needing replacement as the engines get a few years under their belts. This could be the problem, but they're no a cheap part so would be worth double checking stop circuit for loose or damaged wires, etc first just in case you have a issue there. Good Luck

No Crank on Ignition.

By: on 25 June 2024
200 STXRW Yamaha saltwater series 2. Ran new steering cable and have no crank. Turn key to RUN and then jump solenoid and it will crank and run. Question is what wire do I replace? I have extra wire pulled in chase but need to know which to attach to on motor and which to attach to on key switch.

Outboard Spares Response
Hi, If not replacing the loom and just adding a wire to fix the problem it is just a case of running the wire from the stater solenoid to the ignition switch where the crank terminal is. You can find the crank terminal by using a multi meter and check between an earth and holding the key in start position to find the terminal. The multi meter will turn on and off with the correct terminal used when releasing the key from start

2018 Mercury 9.9 2 stroke- no spark

By: on 13 June 2024
This is a Japanese built 9.9, every few months of use it will have no spark. Used multiple times per month- usually a 1 pull to start engine up here in sunny QLD Fresh fuel New plugs Even after having initially run, it may stall from being cold , but then will not fire at all. Dealer cant find issue.

Outboard Spares Response
Hi, If it is a no spark issue and intermittent then I would consider a stop circuit fault. Check for corroded and damaged wires to the emergency stop switch. When the fault occurs, you can also try disconneting the stop circuit wires from the CDI Unit. Be careful though as if the engine starts and runs you won't be able to turn it off until the wires are connected again. Good Luck!

87 Johnson 200GT

By: on 4 June 2024
HI. It doesn't seem to run on all cylinders until the engine is warm. Once the engine runs about 3-5 minutes it all of the sudden smooths out once the other cylinders kick in. It will run great all day until it sits overnight and cools down. I've replaced the CDI on the right side but haven't tried the CDI on the left. I'm also wondering if it isn't the stator or possibly timer base? The stator does have the black goo coming out facing the rear of the outboard. Is there an ohm or other test for the CDI pack or the individual coils?? Thanks for your help

Outboard Spares Response
Hi, It is worth checking the stator with an ohms test. The value can be obtained through a workshop manual or perhaps google based on your model. If it tests ok then continue and check the coils and timer base. Hopefully you can find the problem by doing an ohms test on the individual components. Regards,

2001 Mercury 150 Saltwater 2 Stroke

By: on 1 June 2024
Ran fine about a week ago with the exception of some occasional difficulty with cold starts. Coming back in the other night I backed down from 4000rpm to idle and she cut out. No sputter or shake, just cut out. Tried to restart with no luck. She cranks but won’t turn over. Checked everything fuel related first just to be sure, but figured most likely electrical based on the sudden cut out. Batteries hold a charge, kill switch was checked, has brand new spark plugs, new trigger, just swapped a new CDI, checked all voltage coming from regulators, CDI, etc, checked all connections and wires, still no spark. Only thing we noticed - the stator volt meter reading was lower than spec range. Sooo safe to assume stator issue? Just ordered a new stator so I’m really hoping so…

Outboard Spares Response
Hi, See how you go after fitting the stator. Seems like that is the problem if it was down on volts. They need to be at oem specs to work correctly. Regards,

1994 Johnson 48hp

By: on 31 May 2024
I have a 1994 Johnson 48hp that runs great cold. When it warms up and I decelerate it won't accelerate again until it cools off. This is my first boat and would appreciate any help you have.

Outboard Spares Response
Hi there, It could be an ignition problem. Sometimes the electrical components when they get hot expand and a can lose a solid connection between the circuit. It sounds like that could be the problem. You will need to check ohms resistance of each of the ignition system cold and take down the readings and then try again when hot after it has played up. If everything you test is ok then it could be the cdi which can't be easily tested. You would need to swap it out with another cdi and see if that fixes it. Regards,

1995 Mercury 2 Stroke

By: on 29 May 2024
Hi, I bought this motor after seeing it run fine on muffs. Once I did put it in the water, it did not get up to full rpm when accelerating. I played around with it at first trying to find a leak or some type of air in the fuel system, but did not find anything. The only time the motor ran for at full rpm on the water was after I cleaned the fuel filter. When the motor ran like it should on the water I decelerated and once I did that it would not go back up to full rpm. It has not gotten to full rpm on the water even after a full carburetor cleaning. I checked the compression and both cylinders are at 110psi. There is also spark from both plugs. Not sure what else it could be. Thank you.

Outboard Spares Response
Hi, It could be a fuel pump and carburettor needs replacing/overhauling. Try pumping the primer bulb as you running the motor at full speed and see if the revs pick up. If it does then you'll probably need to service the fuel pump and carburettor while you are at it. Cheers

1982 Evinrude 90

By: on 28 May 2024
Had intermittent spark last year . I replaced all coils, power packs, stator, rectifier and new wires and plugs. I only have spark on bottom cylinders what else would be causing this?

Outboard Spares Response
Hi, The only thing left in the ignition system is the trigger and engine harness which could cause this. I would be looking at the trigger. NOTE: A faulty trigger shorting to ground can blow the SCRs in the powerpacks. Normally you would try and replace the trigger with the packs to ensure one used faulty component won't destroy the other new part. Cheers and good luck.

1988 evinrude vro 250

By: on 24 May 2024
Ran the boat the other day and it died twice , thought it was fuel problem but everything checked out will not start , not even turn over . New coils new plugs and wires new starter and selenoid and key switch . Now I have no clue

Outboard Spares Response
Hi, Remove the sparkplugs and see if you can manually turn the flywheel first of all. If you can't turn it then the motor is seized and requires rebuilding. If it turns over, do a compression test to see if you have compression on all cylinders. If there is compression on all cylinders then it can only be a spark (ignition) problem or a fuel problem. Seeing that you said everything checked out then it could most likely be an ignition issue. Perform a spark test to see if you have spark on all leads. If there is spark on all leads then you might have to go back to the fuel and verify the fuel system which involves checking the fuel pump to make sure it is working and check that the carbies are clean in the bowls and all the jets are free of debris. Regards,

1997 Force 90hp outboard

By: on 27 February 2024
I recently installed a 97 Force 90hp on my boat. During the test run it wouldn't accelerate past 3000 RPM. I'm using the same prop that was on my 1989 Force 85hp so it's not a prop issue. I'm pretty sure it's something with the engine. I have good compression, new and correct spark plugs and the stator ohms out at 654 ohms. I'm not detection any miss fires so I'm stumped. Any ideas?

Outboard Spares Response
Hi there, UPDATE TO ORIGINAL RESPONSE: The 85hp 89 model runs a different ratio gearbox to the 90hp 1997 model. It very well could be your prop is the issue. Make sure it is firing on all 3 cylinders. It may not appear to be misfiring but could be only running on 2 cyl. Also check that there is plenty of fuel pressure. It could be starving of fuel.

2001 yamaha 90 hp 2 stroke

By: on 29 January 2024
I do not have any spark on cylinder 2. The motor won't throttle up for about 20 min. then something kicks in and it will run great all day. I was told it was the cdi so I replaced it and still have the same problem no fire on cylinder 2. Any Help would be appreciated.

Outboard Spares Response
Hi, It could also be a crook coil. A lot cheaper too than the cdi. Also could be a pulser coil (trigger). An ohms test on these components might indicate which is faulty. You will need an ohms meter and manufactures specifications to proceed. Good luck

Mercury 75 hp

By: on 13 January 2024
Hey I have a Mercury 75 hp not sure the year As soon as I put the positive connection on the battery the motor wants to turn over even when the keys turned off ?

Outboard Spares Response
Hi there, You most likely have a faulty stater solenoid. If you remove the small sender wire (yellow) and it still trys to crank you will need to replace the solenoid. If it does not crank after you have removed that wire then check for a faulty ignition switch.

Mercury 90 elpto 1996model two stroke

By: on 11 January 2024
Out of the sea it gets into gear and speeds up normally as soon as I put it in the sea and put it in gear it immediately turns off compression it has good current at the spark plugs normally help me what can be going on thanks

Outboard Spares Response
Hi there, It could be a few things. One is a fuel issue. The other is a ignition/timing issue. It would be very hard to pin point which one without an experienced person take a look at it. Unfortunately there is no quick answer to this problem with your motor. However if you are prepared to have a look into it, I would start with overhauling your carbies, synchronise, and tune them. Check the timing for idle and max spark advance. It could be a faulty stator as well if all the rest fails to fix it. Hope this helps.

2004 mercury mariner

By: on 9 January 2024
I have spark on bottom two spark plugs but not a constant spark on the top, checked stator and black box, all good. How do I check the trigger? Which wires to test between and what are the correct specs? I have a brown, white, black and purple wire. The purple looks like it’s been capped since new. Thank you

Outboard Spares Response
Hi There, You will need to disconnect all the trigger wires from the switchbox/powerpack. Then you can perform an ohms test. Read from Yellow Sleeve to Black Sleeve...Brown to Purple, White to Brown, Purple to White Your trigger should read between 1100 ohms and 1400 ohms between these readings. Hope this helps.

2000 mercury 50hp 2 stroke

By: on 27 September 2023
Boat will throttle up 5100rpm and plane out , then derate to 3000rpm. Carbs are clean, changed fuel lines, plugs. You can push the choke and it will spike to 4000 and idle back down to 3000.

Outboard Spares Response
Hi there, If you are getting the motor to pick up revs with the choke, then it is most likely starving for fuel therefore your fuel pump might not be providing enough fuel at higher revs. I would suggest looking at either replacing the fuel pump or put a new fuel pump kit through it. Cheers

150 Force 1984-89 5 cylinder

By: on 26 September 2023
Hello, I have a 150 force that I just took out with my boat after remodeling the boat for over a year, we replaced the water pump and thermostat before taking it on the river and made sure it idled and ran with a hose and clamp. It ran fine for about 45 minutes and suddenly quit going about 5 mph and wouldnt start half because the battery didnt have enough juice to keep turning it over. I took it home and threw a good battery on it and pulled all spark plugs but it wont turn over. Also I took the motor cover off and tried spinning the flywheel by hand and I can get a full revolution but its pretty hard and a lot of friction. Spark plugs had burnt oil on them too mostly on the top two. Any ideas what could be wrong?

Outboard Spares Response
Hi there, If you can get it to spin over with the sparkplugs removed then try a compression test on all cylinders. Observe the readings. They should all be within 10-15% of each other and well over 100p.s.i. If that fails then you will need to pull the head off and have a look into the cylinders and bores to determine what went wrong.

1997 Suzuki dt 40

By: on 20 September 2023
Hi, I have a 40 hp 2 stroke Suzuki, the last time it was on the water it ran good, full power, for about 2 hours, then it started making this chirping sound almost like a backfire or something. Brought it home now it will on fire one time it will start and immediately die. Let it sit for a couple hours then it will do the same thing. I've tested the ignition system with a dva, and I think my problem is the charge coil is bad. My question is that weird chirping nois, could that be from it not firing correctly or am I looking at another issue altogether? Thanks.

Outboard Spares Response
Hi there, Maybe start with a compression test and confirm all cylinders are even within 10-15% and well above 100 p.s.i. Then check for spark if comps are good. You can check them with a spark tester and make sure there is good spark on all cylinders. It might have sheared a keyway on the flywheel which has put the timing out. If ok then it is a fuel issue. It could be drawing in air in from somewhere around the inlet manifold which is causing it to sound like it is chirping. If you can get the motor to run spray some brake fluid/aerostart around the manifold and see if there is a change in revs. It could also be reeds as well. See if it is pulsing air back out of the carby whilst running. Or it could not be getting enough fuel. Unfortunately is a process of elimination. Good luck

1990 150 Evinrude can over revving cook electric c

By: on 24 August 2023
I have a 1990 Evinrude 150 that I over revved badly. It got me back to the launch just fine afterwards but once I got it home it never started again. It would backfire like crazy but never started. I gave the motor to a buddy who had a spare identical motor with two bad cylinders. He put the motor on his boat and swapped all the electrical components from his to mine since mine had the single power pack and his was the other style. It ran great for about 200 miles. He was running to thru a boulder field and over revved really bad. After a few miles he pulled over to tighten his jet impeller a little bit and afterwards the motor would never restart. It would just backfire just like it had before. Since he changed all the components we never determined exactly which one was bad but the stator was out of spec according to him although it wasn't melted down. Is there a possibility that the cool down after severe over revving could ruin a stator or any other electrical component?

Outboard Spares Response
Hi there, Yes, electrical equipment is responsive to heat. it would be best to do an ohms test on all components to make sure they are still within specification.

1985 Mercury 115 high rpm miss

By: on 22 August 2023
Hello, I have a 1985 mercury 115. Engine runs great at idle and low rpm. When accelerating to WOT the engine begins to miss. Seems as though it is dropping a cylinder and occasionally the cylinder will come back and the engine will run fine for a couple seconds or so. Tried cleaning carbs but no luck. Stator and power packs are only about a year old. Power packs were not OEM so wondering if that could be the problem

Outboard Spares Response
Hi there, I wouldn't assume it is the aftermarket powerpacks without checking the coils first. A coil could most likely be the problem. You will need to do an ohms test and see if one of the coils stands out to be different to the rest. If so, then replace that coil. Hope that helps.

86 Bayliner capri w/85 horse Force Outboard- Click

By: on 12 August 2023
Am having a frustrating time trying to figure out why the motor won't crank over. It works very intermittenly. Have cleaned up the wires and connectors, replaced where necessary and replaced the solenoid. When I push the ignition key down, the choke engages making a clicking noise, but nothing happens when I turn the key to start. The neutral switch moves properly. And yes, I'm pulling the handle out and rotating it forward. Any Ideas?

Outboard Spares Response
HI, Have you tried disconnecting the neutral switch from the circuit? I know you mentioned it "moves properly" but you could test the switch is actually working correctly OR just remove it from the circuit temporarily to see if it resolves the issue. Otherwise, it could be the brushes in the starter motor plate are worn and due for replacement.....just a thought. Good Luck!

75 HP Mercury 2 stroke

By: on 8 August 2023
My 75 HP Mercury 2 stroke idles fine, but when you speed it up, it starts missing. I have cleaned the carbs, replaced the spark plugs and replaced the coils. Any other suggestions?

Outboard Spares Response
Hi there, It could be either stator, trigger or maybe powerpack. You would need to test these parts with an ohms test except for the powerpack which you cannot ohms test. Start with the stator and trigger. If these turn out to be ok then it will be most likely the powerpack. Good luck

1986 175 Mainer

By: on 5 August 2023
Engine was getting hard to start but ran good after got it going. I started checking for fire by grounding out plugs only got #1 plug to fire.. let it rest came back put muffs on it I started right up crazy!!! Took it out on water no problems. Bought a spark tester checked spark only1 plug fired. Ordered two power packs installed all cylinders fire starts right up ran good on muffs.. put boat in water only turns around 2500 rpms full throttle miss sound.. I did Chang the idle speed control too.. also at one time I had the ignition switch stay on starter kept turning..

Outboard Spares Response
Hi there, It could also be the high speed circuit in the stator. You will need to do an ohms test to check it against manufacture specs Hope that helps. Cheers

1984 Mercury 75 hp 2-Stroke

By: on 1 August 2023
My 1984 Mercury 75 hp 2-stroke will start and run with full throttle but dies as soon as I bring it to idle. I tried to shock it with Sea Foam but that made no difference. Why would it run at full throttle but die as I lower it to idle... every time?

Outboard Spares Response
Hi, It could have an exhaust leak. See what happens if you run it without the engine cover on... Also I'm assuming it is the 4 cylinder model given the year, if so it could be running on 3 cylinders not 4 hence at lower RPM it wants to stall as it's trying to carry the lazy cylinder. Get a spark tester and check all cylinders for spark and see how you go. Good Luck!

95 force/mercury

By: on 29 July 2023
Motor was running good except a idle or carburetor issue but the starter went out. I replaced the starter with a new one but while I was waiting on the starter I put in a new set of dash switches and a new fuse block, I needed another switch for a radio and the old ones were pretty bad. Once the starter was in I have not even been able to get it to fire. Seems no spark on the plugs. I didn’t really mess with the starter switch other than tie to the accessories pin. Like it’s grounded out.

Outboard Spares Response
Hi there, You may have the kill switch wire incorrectly connected to the ignition switch. Maybe try disconnecting the kill switch wire from the circuit and see if you get spark. It will not spark if that wire contacts ground. Cheers

1997 Johnson 50 hp 3cyl, 2 store

By: on 21 July 2023
Hi, I have a motor that has no spark on any cylinder. Got it back from the repair shop and they put a new CDI power pack in it. He was still a little iffy on it. It did not have any spark when i got it home. I tried a new(used) kill switch/ throttle box assembly he had sitting around and still did not have spark. Possibly something in the stator? Thoughts?

Outboard Spares Response
Hi Derek, We find with these engines that you should be replacing the Timer Base (Trigger) and Powerpack (Switchbox/CDI) at the same time. A faulty Timer Base with a short to ground will cause premature failure of the Powerpack and Vice-Versa. This is what I would be checking. Good Luck!

1987 Mercury 2 stroke 90hp

By: on 18 July 2023
I have a Mercury 2 stroke 90 hp engine. This has happened twice, now. I start the boat, run around for a while, stop to fish for an hour plus, and when I try to start the motor, it turns over and maybe coughs but will not start. I get the impression that it is flooded, but if that is the case, then why? This has only happened when it has been run, then sat in the water for a bit. I took it to the dealer, where it ran like a champ, of course. Thanks!

Outboard Spares Response
Hi there, If it is flooding it will be hard to start. This can be due to the needle and seats in the carbies are worn or there is some debris in there. Try priming the primer bulb firm and seeing if there is any fuel leaking out of the carbies first. If there is fuel leaking then your carbies will need an overhaul. Cheers

1974 Mercury 500 Thunderbolt 50HP - low RPM when i

By: on 10 July 2023
I have a 1974 mecurcry 500 thunderbolt. Out of the water the engine seems to run fine and hits full rpm, but once in the water it seems to loose all it's power. I checked the exhaust, impeller (found tear in gasket), compression, cleaned carb and changed faulty wiring. I even took it to a mechanic and he couldn't find anything wrong with it on his end. Been searching online and can find lots of people with similar issues, but really no information on what's wrong and how to fix it.

Outboard Spares Response
Hi there, Check your ignition system. A stator can be a likely cause for this problem to occur. Do an ohms test on the stator to make sure it is within specs. Cheers

2000 Evinrude Ficht not firing on 1 cyulinder

By: on 2 July 2023
Took boat out today. Started and ran fine until i passed the breakwater. Put throttle on her and ran for about 10 minutes and then slowed down and stopped. I was able to get the boat back to the slip at slow(rough running) pace. CHecked engine at slip and it appears one cylinder is not firing. How to determine if its a coil, injector or sparkplug? Sparkplugsw were just replaced and cylider compression tests taken (all good)

Outboard Spares Response
The FICHT engines can be tricky to diagnose. You could take it to a dealer and have them plug it in and check for a fault code.. Sometimes these earlier FICHT models won't supply any fault codes if the ECU itself has an issue. If you find yourself in this position (no fault codes) I'd contact DFI Technologies in Alabama. They specialise in FICHT ECU repairs. Cheers

1981 evinrude 35 horse electric start with key no

By: on 28 June 2023
Hoping you van help me out. Recently bought a non running old boat to redo for fishing. When i put a battery in it, it seems to crank over just finr, but it does nit send spark through the plugs. I tried a shot of starting fluid in each cylinder and it did nit fire ciugh sputter nithing nada. Im trying to identify the souce of the problem without just throwing expensive parts at it. I cleaned iff the ground connections for both coiks and the CDI still nothing? Where to go from here? Thanks for any assistance you can provide.

Outboard Spares Response
Hi there, Try disconnecting the kill switch wire from the circuit and check for spark. It could be a faulty kill switch or ignition switch. Hopefully you can get spark which will be the quickest way to find out. If no spark then you will need to check the ignition system.

1985 Mariner

By: on 28 June 2023
Have 1985 mariner 50hp that will turn over but not start, changed the spark plugs and put fresh gas still does same thing

Outboard Spares Response
Hi there, First you will need to check for spark. If there is spark then check compression. If all good then there is a fuel issue. Start by using some aerostart in the carbies whist cranking the engine over and see if it starts. If it goes to fire then you might have to overhaul your carbies. Cheers

Mercury 2002 90hp 2 stroke

By: on 17 June 2023
Low power when getting on plane then when approaching WOT flutters and loses power. Starts cold and idles great in gear. Bit of trouble starting warm after shutdown. I rebuilt the power head due to worn rings (85 psi)but this problem existed beforehand and the reason I did the rebuild. Now have 115 psi compression and didn’t solve the issue. Timing and linkages all reset and triple checked. Checked the Carbs, rebuilt fuel pump twice and tested, replaced fuel filters, pumped primer bulb running, ran off portable tank with no change. Replaced plugs and wires, showing spark on all cylinders running by removing 1 by 1. Ohms tested all CDM’s and Stator all good. No carbon at all on plugs they appear almost like new with a little oil on them at about 50 hours run time after rebuild. That seems a little odd, I can see one cylinder getting water intrusion but all 3? Hope your still answering, you are very knowledgeable

Outboard Spares Response
Hi there, You say water intrusion. Well that is a problem. You need to solve that issue. There should be no water getting in. There could be a few ways the water is getting in. Start by having a look at your exhaust plate and check for pitting or cracks. It might be best to put in a new exhaust plate in even if looks slightly corroded. Hope that starts you in the right direction.

Mercury 135 v6 -98 die/won’t rev more than ~2000ro

By: on 7 June 2023
Hi, I’ve got a merc v6 that sometimes struggle to rev up when accelerating. The engine stalls/dies at approx 2000 rpm. Seems like I only have spark on one cylinder bank, suggesting ignition boxes. I’ve tried to change the ignition boxes but still same issue. Usually works fine when engine is cool, or is running. But if I stop and let it sit for 15-30 min, the issue will appear. Can it be a heat issue connected to stator? Or rectifier? Thanks!

Outboard Spares Response
Hi there, If you have swapped switchboxes over and there is no change with the spark output on the bank then most likely it is a stator. You can test the stator with an ohms meter to check that is within spec. Cheers

2002 Mercury 60 HP 2 Stroke

By: on 3 June 2023
I have a 2002 Mercury 60 HP 2 Stroke engine that starts fine idles fine runs great up to a certain RPM and then starts to sputter and won't go any faster, top speed on my boat is 26 MPH and will only go 12 MPH and the starts to sputter. replaced the fuel pump went thru the carburetors still the same results. Any Ideas?

Outboard Spares Response
Hi, I'd be checking for spark. It very well could be a faulty coil as these models (from memory) run a CDM type coil x 3. If one of these coils is faulty the engine won't achive required RPM. Good Luck.

Started misfiring on 2 cylinders 94 yahmaha 115 2

By: on 3 June 2023
We would run it and it would be fine. Full Is throttle idleeverything. Then all of a sudden we. Notice that it would. Stop firing on 2 of the cylinders. We realized this because it just started putting along. So we changed the coils we changed the spark plugs and that's how we realized. It was just firing on 2 cylinders because only 2 spark plugs were dirty. So then we replaced the stater and now it won't even turn on. Please help!

Outboard Spares Response
Hi there, I would test both stators and make sure they are ok. It could be that you have a faulty trigger or switchbox. Test the components with an ohms meter and make sure they are within manufactures specs. You may have a faulty switchbox

1976 100 horse johnson

By: on 31 May 2023
Just got this boat don’t know a hole lot about it fired it up brought it to lake and it run’s horrible doesn’t hardly idle no throttle response back firing a lot any advice part of me says fuel pump but thinking might be spark related can’t find any information on this motor

Outboard Spares Response
Hi there, First check that you have spark on all cylinders. If you don't have spark on all cyl then you will need to check the ignition system to determine which part is faulty. If you do have spark then would be best to remove the carbies and overhaul them. Cheers

No spark

By: on 27 May 2023
I have a 1978 Johnson outboard 115hp v4 and I have power to the the coils but no power in the plug wires. Needing some advice

Outboard Spares Response
If you have voltage input to the coils but no spark (ie no voltage output) then it is most likely the coils that are faulty. However it is unlikely that are 4 coils are faulty. I would make sure that the voltage input is correct. You can check this while cranking the engine and making sure all 4 are the same with a voltmeter and within spec.

1986 Mercury Black Max 175 Hp no spark at all

By: on 27 May 2023
I have a mercury that I tried to start this year, no spark. I unhooked all the kill wire (3) black yellow trace. I replaced the rectifier and trigger, both tested bad, also mouse chewed through all stator wires so I even replaced the stator. Everything is hooked up correctly and I still don’t have any spark at all all 6 cylinders…… I am stumped. Checked all wires and connections all good nothing further chewed or broken… Battery is at full charge. Neutral switch test good as well….. I’m totally at a lose here can you please help me?

Outboard Spares Response
Hi there, It only leaves your switchboxes and coils that haven't been replaced. Most likely you have faulty switchboxes.

99 Johnson 2 stroke throttle issues

By: on 23 May 2023
Hi OBSpares, we recently had a part changed because it was smoking a lot. Since then we put the boat in the h20 for the season and now we have the issue of when trying to accelerate the throttle it just bogs down and stalls out. It’s doesn’t seem to be anything with the fuel but possibly something with the electrical. Any ideas?? Appreciate any help. Thanks

Outboard Spares Response
Hi there, First I would start with a spark test and make sure all sparkplugs are firing. This will determine if it is electrical or fuel related.

1986 mercury 75hp 4 cylinder

By: on 22 May 2023
Coil arcs to nearest metal where the hot lead comes out. I’ve replaced coil, and he lead, and spark plug but it still arcs on coil number 3, even when changed! Really stuck, the engine is now constantly firing on 3

Outboard Spares Response
Make sure there is a good earth on the coil

2005 yahama 175 hp hpdi

By: on 22 May 2023
Engine idles great in gear, might be a little high but when l put it in neutral it wants to flutter or feels like it’s missing. Runs great down the lake at all speeds.

Outboard Spares Response
Hi there, That is the design of that motor. It runs on 3 cyl in nuetral to allow easy shifting into gear. Nothing to be concerned about. Cheers

1998 evinrude 2 stroke

By: on 17 May 2023
When I first try to start my motor it will crank but take a several minutes to actually start, but it will only start for about 1-2 seconds before Dying again. After about 20 to 30 minutes of this when I assume it’s getting warmer it will then finally stay running but even then it will die if I give it any throttle. After idling for about another 10 minutes I can finally give it gas and it will stay running. Any help would be nice

Outboard Spares Response
Hi there, It may not be getting enough fuel. Remove airbox. You can try to start it with some aerostart to see if it makes it easier to start. If it does then it is not getting enough fuel. You will then need to remove the carbies and overhaul them paying attention to the idle circuit to make sure everything is clean.

1996 evenrude 115 (e115tleda) voltage drop and hp

By: on 16 May 2023
I have an issue where there is a voyage drop when starting, using electronics or nav lights. It is Hard starting. I can not get to plane and is topping out at around 2500rpm. Seems to run ok with muffs but still some voltage drop. Other symptoms are that the tach, speedometer and gas gage stop working at random. I have replaced the ignition switch, spark plugs, battery, and rectifier but the issue remains. Thanks in advance for any advice!

Outboard Spares Response
Hi there, There will be a voltage drop when starting. That is normal. You need to check what volts are going to the battery when the motor is running. It should be 12.6-14.5v. It could be that the charge coil in the stator is not supplying the correct voltage to the rectifier. Also if the motor is not revving above 2500rpm you might have a stator problem.

150hp 2 stroke johnson

12 May 2023
My motor runs fine on idle then when we take off it idles down and stops unless priming the bulb. I think the motors not getting enough fuel.

Outboard Spares Response
Hi there, Sounds like you need a new fuel pump. Cheers

1987 mercury 20 hp when cold will jump up and run

By: on 9 May 2023
After stopping to fish it will not come up to speed ,runs ruff .coils or CDI? I think I am only running on 1 cylinder . Later on will start up and do the same. Any help is very appreciated

Outboard Spares Response
Hi there, See which sparkplug is not firing. Swap coils over with each other and see if the spark swaps over. If it does then most likely a coil. If it doesn't (no change) then most likely a switchbox

1991 Evinrude 200xp major electrical issues

By: on 9 May 2023
I carried my Stratos bass boat to the lake and only ran it about a mile, loaded it back on the trailer, went home and put it in the garage. It ran fine but my steering cable broke. Went in the house and looked up a new steering cable for it, around 8 o’clock that night ( about 4 hours after getting back from the lake ) I went to measure my cable to order the right size. Upon opening the garage door the whole garage was full of smoke and smelled like wires burning. I unhooked the battery and let the smoke clear. Upon inspection of the motor the power pack, stator, rectifier and part of the main wiring harness were all melted. Any ideas on how or why this would happen when the boat wasn’t running.

Outboard Spares Response
Hi there, You might have had a faulty rectifier which can do this under certain circumstances. It is always good idea to have battery disconnected when not being used for many reasons this being one of them. Lucky you got it before any further damage

1980 Johnson 35hp 2 cyl

By: on 8 May 2023
Last summer had no spark and it was the coil packs. This year no spark. Spins over great won’t start hot battery grounds clean and check out good. Any ideas on which part is the best bet to replace or how to check possible components with an ohm meter. Any ideas are appreciated

Outboard Spares Response
Hi there, First check the kill switch with an ohms meter. It should have full continuity and none between on and off. Keep it disconneced from the circuit and recheck for spark. If still no spark then it is most likely the powerpack. It can't easily be checked so best to buy a new one.

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