Carbon fouled plugs

[Hoquat]

I own a '76 Catalina 27 with an Atomic four and I am having difficulty with my plugs fouling within about 30 hours of use. Definitely carbon, not oil, thank God. Anyway, the engine starts to miss and eventually will refuse to run when put in forward. Change the plugs and it purrs like a kitten. I can't seem to lean out the carb to fix the problem. What am I missing here?

[marthur]

Fouled Plugs

I've got a '77 C-27. I will get a little carbon on my plugs after prolonged slow speed or idling, but nothing like your symptoms.

Since a rich mixture is always my first thought, you might check things other than the mixture screw that can give you a richer mixture. Like an incompletely opening choke or clogged air cleaner flame arrester. In fact, I had exactly the same problem on a different type of boat motor and the symptoms were resolved after I rebuilt the carb and replaced the float.

You might also look for worn breaker points or retarded timing. I would also check for corroded or cracked wires on the affected plugs. Also look for cracks in the distributor cap between the towers of affected cylinders. Make sure your coil wires are in good shape.

Low compression might also be a factor (lets hope not!).

Good luck!

Mike

[Hoquat]

Thanks for the responce. I had checked the choke and the spark arrester but not thought about the float which could be the problem. Looks like I'll have to pull the carb and check it out.