NEED HELP Force 85 fire on 1 Cylinder

[bigmike2]

I have a force 85 it has fire on only 1 Cylinder the other 2 don't have any fire I was wondering if anyone might know what the problem is

 

[pnwboat]

Re: NEED HELP Force 85 fire on 1 Cylinder

What year motor? Need specifics on which cylinders do and do not have spark. No.1 cylinder is at the top. No.3 at the bottom. Sounds like a possible bad CD module.

 

[rsw21282]

Re: NEED HELP Force 85 fire on 1 Cylinder

i had some similar problems but it depends on ur ignition sys. i have the prestolite and my prob was a combination of things, 1 bad cd box and 2 ignition coils. bad thing about these components is there a bit harder to test for proper operation(atleast for me im a beginer) i do know on my motor that 1 cd box controls the 1&3 cyl while the other fires the 2nd. so if similar system i would check the cd box and coils

 

[1fullforce]

Re: NEED HELP Force 85 fire on 1 Cylinder

i would start with checking to see if the spark plugs are good by replacing the ones with no spark with a known good spark plug. if still no spark i would look at the electrical system diagram on the repair manual for your engine, on the 1987 85hp force the 1st cd module controls the 1 and 2 cylinders and the 2nd module controls the 3rd cylinder. make sure the wires behind the cd modules (red and orange) are plugged in the ignition coils correctly. inspect all the wires from trigger housing and do the same to the stator's wires make sure they are clean and tight at the ends. if you think u got a bad cd by now, then switch the cd that has spark to the other cd with no spark. if now u got spark to the other cylinders u did not had spark before and no spark to the one u had before. you found your problem , or still no spark? may be the trigger or gone bad, or the stator . test the trigger first.

 

[john from md]

Re: NEED HELP Force 85 fire on 1 Cylinder

One thing to remember about CDI ignition systems. You never want to spin or run the engine with an open plug circuit. You must either ground the coil wire or the plug shell before rotating the engine or you will destroy the CDI module. You can buy cheap 18ga jumper wires in Pep Boys or Radio shack that have alligator clips on them. These work fine when troubleshooting.


Full force has given you the steps to follow. Make sure your battery is fully charged before starting the process.

Regards,

John

 

[bigmike2]

Re: NEED HELP Force 85 fire on 1 Cylinder

Thanks for all the info. #1 and #3 no fire #2 has fire put new plug in 3 still no fire, the back side of 1 & 3 coil looks like they have gotten little pen holes in them #2 coil looks good. So I guesss 2 coils is a good starting place what ya'll think

Mike

 

[john from md]

Re: NEED HELP Force 85 fire on 1 Cylinder

You can check the coils with an ohmeter to see if they are good or not. The manual will have the resistance readings. I have little pin holes in mine and they still run fine.

John

 

[Shifflett115]

Re: NEED HELP Force 85 fire on 1 Cylinder

had pretty much the same problem and it turned out it was the cdi box,so i would start there because it controls the coils that are not firing

 

[1fullforce]

Re: NEED HELP Force 85 fire on 1 Cylinder

switch either #1 or #3 ignition coil with the #2 good coil to see if they are defective.

 

[bigmike2]

Re: NEED HELP Force 85 fire on 1 Cylinder

Now a few days later no fire on any of the plugs. How do you check the trigger to see if it's good or not, also the stator

 

[john from md]

Re: NEED HELP Force 85 fire on 1 Cylinder

If you look in the electrical part of the manual, it will tell you where to check for resistance and continuity.
It gives specific readings that you should get for the stator, trigger and coils.

Good luck,

John