Fouling plugs

[ANetzer]

I am in the process of buying a sailboat with my first Atomic 4. The seller told me that the #1 cylinder fouls regularly, and that by putting 'restorer' into the oil at changes it has significantly reduced the interval between fouled plugs. The engine appears to run well, smooth...so I'm guessing its a oil ring. A respected auto mechanic also suggested running a heavier wt oil. Ultimately I may change the rings...what are your thoughts on the restorer and heavier wt oil?

[randall]

I just bought a used A4, and it had a similar problem. Don always suggests, and I always use straight 30W oil, but you would be amazed what Marvel Mystrey Oil can do. Try a search of the Guest Log on MMO.

I also used another product, and it was a fabulous fix... Go to this thread to see how I solved my problem.

http://www.moyermarine.com/forums/showthread.php?t=821

You might also try hotter plugs... I read somewhere here that Don recommended Champion RJ12YC... it has a longer ceramic, and appears to go into the chamber more... hence burning off better. That's my next step.

[Don Moyer]

Your current suggestions could be of benefit, and I also recommend checking the compression, particularly in the first cylinder. If the compression is very low (50 psi or so) there's probably nothing that can be done to completely remediate the plug fouling.

You may also be able to improve the compression a bit by squirting 5 or 6 squirts of Marvel Mystery Oil (MMO) into that cylinder (aiming it away from the manifold side of the engine) and then burning it off. Do this several times. If you can get the compression above 60 psi or so, continued use may improve it further. It's frequently the case that Atomic 4's suffer from nothing more than too infrequent use.

Don