86' 125 Force choking at startup or is it backfiring?

[iwaterdave]

I had this motor running this morning. It was not great sounding but was running on the hose none the less. I got it on the water and only 100 feet from dock and it cut out with no power. It now won't start... This video now shows what I'm experiencing. I'm at a loss of what to fix cause I've never seen this before.

 

[flyingscott]

Check the flywheel key could be sheared

 

[iwaterdave]

No Title

I tore off the flywheel and looked at stator and key and everything looks ok to me but I've only replaced one when it was obviously cracked. Here are the pictures.

 

[Jiggz]

Why start with something so complicated with troubleshooting is really beyond me. When troubleshooting always start with the easy and obvious ones first and then moving on to complicated stuff like removing flywheel. Now with the flywheel off, there's really nothing you can do to troubleshoot anymore except maybe to take resistance of the stator, etc. I can see a clear fuel filter between the fuel pump and the carbs, is this at least half filled? Do you have sparks on the plugs? Did you try spraying fuel oil mix directly into each carb and see if it "cough"? If there is no sparks in the plugs is the kill switch fully reset? Have you tried disconnecting the white kill wire off the terminal board and see if that makes a difference? Note with the white kill wire disconnected the motor may start and you have no way to turn it off. To do so you will need to re-ground the white wire but make sure you are insulated from it.

 

[jerryjerry05]

If anyone can tell if a stator or trigger is bad by looking at it then I need to study under that guy!!!
​Outboard ignition dot com has test procedure.

From the video: Do a compression test before you do anything else.
Then do as Jiggz suggested.
Get a manual. Your local library might have one??
They sell them here. E-bay is the best place to get factory manuals.

 

[iwaterdave]

If anyone can tell if a stator or trigger is bad by looking at it then I need to study under that guy!!!
​Outboard ignition dot com has test procedure.

From the video: Do a compression test before you do anything else.
Then do as Jiggz suggested.
Get a manual. Your local library might have one??
They sell them here. E-bay is the best place to get factory manuals.

​Compression test was 120 +/- 5 pounds in all cylinders. The last stator I replaced had obvious crack in the housing and burnt wires. I'll look up the testing procedure and try that today.

 

[iwaterdave]

Today I trouble shoot the fuel and electrical. Tore off all the fuel lines and cleared everything out. Then disconnected the electrical packs and now the motor turns over without interruption. Some how something went bad or I hooked it up wrong...

 

[iwaterdave]

Why start with something so complicated with troubleshooting is really beyond me. When troubleshooting always start with the easy and obvious ones first and then moving on to complicated stuff like removing flywheel. Now with the flywheel off, there's really nothing you can do to troubleshoot anymore except maybe to take resistance of the stator, etc. I can see a clear fuel filter between the fuel pump and the carbs, is this at least half filled? Do you have sparks on the plugs? Did you try spraying fuel oil mix directly into each carb and see if it "cough"? If there is no sparks in the plugs is the kill switch fully reset? Have you tried disconnecting the white kill wire off the terminal board and see if that makes a difference? Note with the white kill wire disconnected the motor may start and you have no way to turn it off. To do so you will need to re-ground the white wire but make sure you are insulated from it.

I don't know how to test voltage. Any good how to video's? Replaced the fuel filter today but it was also 3/4 full. No spark in any plugs. Then occasionally I will get some spark and it will fire up only to run like crap. Kill switch is fully decompressed. Havent tried the Kill white wire yet. BUT I did notice something today. I disconnected the power packs and now the motor turns over faster without interruption like in the video... What does this mean?

 

[Jiggz]

It sounds like either plugs, coils or CDM's are not connected properly to their designated cylinders or it could be the trigger wires are not connected appropriately with their designated CDM circuits. You need to validate all wiring is done correctly. If you do not have a wiring let us know and we can post one.

 

[iwaterdave]

It sounds like either plugs, coils or CDM's are not connected properly to their designated cylinders or it could be the trigger wires are not connected appropriately with their designated CDM circuits. You need to validate all wiring is done correctly. If you do not have a wiring let us know and we can post one.

I don't have a wire diagram . Please post if you have available. I did get it started on two cylinders so I'm pretty sure what pack is not set up correctly.

 

[Jiggz]

No Title

Here's one. You might have to save it and then enlarge it before printing to make it readable. I am assuming you have the prestolite system.

 

[iwaterdave]

Here's one. You might have to save it and then enlarge it before printing to make it readable. I am assuming you have the prestolite system.

So the wire diagram was not readable when I printed it. So I did some searching and found another one. I'm guessing they are pretty much the same. So I got it started but it still has a bit of a interruption in the running process. Do you think this is a miss? I just re did all the fuel lines and cleared all the passage ways.

 

[iwaterdave]

No Title

Here's one. You might have to save it and then enlarge it before printing to make it readable. I am assuming you have the prestolite system.

i sih​This is the diagram I found online.

 

[Jiggz]

Well that is progress. Yes, there is a miss. The video is not long enough to determine if the miss is constant in time interval. If it is constant in time interval it could be fuel related, i.e. the bowl empties after so many rpms or it could be reed valves. But if it is not constant in time interval it could be electrical meaning the spark sent to the plugs may not be constant due to CDM capacitor problem or it could just be the spark plugs missing. Start with the fuel first by watching the clear fuel filter. After running for a while it should at least be 3/4 full even at idle. If the fuel level goes down to 1/2 full, then the fuel pump might need some work but before doing that watch the clear fuel filter for bubbles. Bubbles indicate air leak from the suction side or a leaky diaphragm. If there are no bubbles but the clear fuel tanks does not reach 3/4 full, then there could be restrictions on the suction line or it could be the fuel pump is leaking and needs overhaul or at least the diaphragm to be replaced.

To check if it is electrical is to use a conventional inductive timing light, Using a dark colored paper connect the timing light on each of the plug wires while the motor is running. Bounce off the timing light to the dark colored paper and watch for consistency in the strobe light. If there is inconsistencies the electrical problem could be with the CDM or the trigger. If there is no inconsistency, then you need to have brand new spare spark plugs to make sure it is not the plugs causing the misfires.

Misfires are the hardest to troubleshoot and you have to rely on process of elimination to fix it. Do not expect to fix this in a day or even a weekend unless you get really very lucky. The fuel recirc system can also cause misfires but first you need to make sure it is not electrical or a fuel delivery problem.