1990 Force 120 No #4 Cylinder

[bigmatt14]

First post guys. Great forum.

I have a 1990 Force 120 that is running on 3 cylinders. The #4 cylinder isn't firing. Compression tests match top to bottom, as does the spark in all 4 cylinders. Sprayed all the intake gaskets trying to create a seal in case I had an intake leak and nothing.

Anybody have any idea what's going on, good compression, good spark, new plug, still not firing?

Thanks for the help guys.

 

[bktheking]

Re: 1990 Force 120 No #4 Cylinder

Stuck open reed will do this, causes the cylinder to fill with too much fuel, compression and spark check out but it just won't fire.

Been there with the same issue, just a different motor.

 

[bigmatt14]

Re: 1990 Force 120 No #4 Cylinder

Stuck open reed will do this, causes the cylinder to fill with too much fuel, compression and spark check out but it just won't fire.

Been there with the same issue, just a different motor.

Can this be cleaned and fixed, or does this have to be replaced?

 

[roscoe]

Re: 1990 Force 120 No #4 Cylinder

replaced as they are usually bent or broken

 

[bigmatt14]

Re: 1990 Force 120 No #4 Cylinder

replaced as they are usually bent or broken

Costly?

 

[thompy]

Re: 1990 Force 120 No #4 Cylinder

ccms after market reeds are under 100 dollars, boysen a little over, but sound like the boysen dont hold up as well, the stock ones are steel dont have a clue on price, the reeds are in behind the carb manifold

 

[bktheking]

Re: 1990 Force 120 No #4 Cylinder

All depends on the situation, in my case a zip tie was stuck in the reed plate holding a reed open, all I did was remove the tie and I was back in business. Reeds aren't expensive, you'll need to pull the carbs and manifold to investigate.