85 hp force

[joseph j]

i have a 1984 85hp force 3 cylinder outboard and i cant get the bottom cylinder to fire... i switched the cdi boxes and it will fire so i put a new box in.. unfortunatey that was not the problem..any ideas on what is causing this to happen?

 

[Frank Acampora]

Re: 85 hp force

If you switched boxes and it did fire, you have proved that the stator and trigger are OK.

Put on the old box and switch coils. If it fires, the coil is bad.

 

[joseph j]

Re: 85 hp force cylinder wont fire

Re: 85 hp force cylinder wont fire

when i switch the boxes the cylinder will fire...so how can the coil be bad?

 

[Frank Acampora]

Re: 85 hp force

Yes, point taken. Chalk it up to me working too many hours.

in 1984 the engine had Prestolite ignition with quick connect electrical wiring. If your old box fired the cylinder and the new one does not, then we need to prove the new one is good. So, you should connect the new box to the upper two cylinders and see if you get spark on both. If you do, then the problem would most likely be in the wiring, either to the box or to the coil. This one will take a bit of time and thought on your part.

Now, you have already said that the top box will fire the #3 cylinder so if the new box will fire #1 and #2, use it on them and the old proven box on #3

 

[joseph j]

Re: 85 hp force

ok here is what i did, when the boat lost power last summer i found that the bottom cylinder wasnt firing, so i switched wiring to the boxes to see if it would fire... it did..but then one of the others wouldnt, so i assumed it was a bad box...i bought the new box and installed but it does the same thing, so im assuming the coils are good... this is were i get confused ..could the stator be bad, trigger, rectifier???? i have a service manual on the way, but i was hoping to find someone that has been through this before. i do appreciate any input because im stumped, and im pretty good mechanically but electric confuses the hell out of me

 

[jerryjerry05]

Re: 85 hp force

Do another compression test. I had a motor with good compression but the head had developed a small spot that was allowing water in.
It would run for a bit then get warm and screw up.
If your getting spark but it's still not running maybe a new head gasket.
I had to get my head resurfaced. Something to think about.J

 

[dougl58]

Re: 85 hp force

I had the same problem with my Force 85. I received the suggestion to check the fuel pump diaphragm. Sure enough it had a tear. Seems it leaks fuel down to the bottom cylinder.

Unfortunatly when I replace the diaphragm I enountered problems... thus my posting here.. Pump Diaphragm Blues! Still working on it and looking for help.

Check the fuel pump diaphragm... but wait till I find my fix before you change it ! LOL