88 85hp bottom cyl no spark

[redspitster01]

Hi Guys,

Trying to figure out my no spark on the bottom cylinder issue. occasionally it will spark for 10-15 seconds on startup but then dies off. Swapped around the coils and all appear to be working correctly. Followed the troubleshooting guides and checked resistance of trigger- ok. checked resistance of stator all ok. also checked these to ground and all is ok.

So I got myself a DVA adapter and started checking voltages- Trigger ok, Stator only has 12V instead of the 300ish volts I see on the working part of the stator.

So I have a stator that ohms out ok, but will just not produce much voltage...... Anybody ever see this before? I went ahead and pulled the flywheel and the stator looks ok, no burns, melts, bare wires etc. Looks normal.

Any ideas?

 

[Jiggz]

Re: 88 85hp bottom cyl no spark

Have you tried swapping CD modules? #1 & #2 cylinders are fed from the same CDM while #3 is fed from the 2nd CDM (albeit only one of two ckts is being used, hence a spare one) By swapping you can tell if the problem moves with the CDM and indicates fault. As for the stator output, I believe you are reading from the charging coils and not from the power coils of the stator. Make sure you read output voltage from the blue & yellow wire combo (there are two sets of them) and the expected output voltage should be around 180V.

 

[redspitster01]

Re: 88 85hp bottom cyl no spark

I am measuring the blue/yellow wires which go on to the CDI box so defiantly not the charging coils... Same measurement on the other working set of blue/yellow wires yields the proper voltage.

I ohm'd the stator and it was ok so I hooked up the 2nd unused side of my CDI box and still a no go so I went a new CDI box (ouch..) same result. Then I got a DVA adapter and started looking at voltages and found what looks like a low one.

 

[Jiggz]

Re: 88 85hp bottom cyl no spark

You can try swapping the yellow & blue wires with the CDM it feeds and if the problem shifts to #1 & #2 cylinder, definitely the problem is with the stator ckt. You can try tracing the wires all the way to the stator and hopefully find what is causing the low voltage. it could just be a lose wire connection or frayed wire. If there is nothing obvious, then it's time to get a new stator. Goodluck.

 

[ferdly1]

Re: 88 85hp bottom cyl no spark

I may be wrong but I am thinking bad trigger.