decarbon/ fouling plugs

[Matthew A.]

I recently decarboned my 85 hp 1988 force engine using Johnson/Evinrude engine decarbonizing spray. The instructions recommend allowing 3 to 16 hours of soak time before running the motor. I let the motor sit for 4 hours before runnning the motor to "blow out" the resulting carbon. However, ever since then I have been noting sticky deposits on the face of the gapless spark plugs. These deposits at times are enough to cause plug fowling on no. # 2 and 3 cylinders. No. # 1 cylinder spark plug remains fairly deposit free. Hmmm? Requiring they be removed and cleaned inorder to get the motor running once again. My question regards whether or not I should decarbonize the motor once more and let sit for longer? I had this problem once before after using Sea Foam gas additive decarbonizer. However, running the motor without the additive solved the prob. I have gone thru the electrical system several times looking for loose or broken connections that might explain why #2 and #3 cylinders spark plugs is more prone to fouling then # 1 cylinder and found nothing a miss.

 

[roscoe]

Re: decarbon/ fouling plugs

Do it again, you still have a lot of crud in there that needs to be removed.
Warm up engine, spray it in, let it sit, spray in another can while you are blowing it out.

""I had this problem once before after using Sea Foam gas additive decarbonizer. However, running the motor without the additive solved the prob.""

That didn't solve the problem, just masked it. The real problem is that there is a lot of crud in there that is hurting the engine and the performance.

The reason this is showing up on the #2 and 3 cylinders could be that the carbs are out of adjustment. Too rich or too lean, on all 3 carbs.

Might be time to have them adjusted.