Reply To: bottom cylinder fouling Big Twin 25hp

[Don]

Buccaneer wrote:

What about the “oil drain system” and that little flopper check valve in the front crankcase cover.
If that’s not working will you get excess fuel and oil in the bottom cylinder, causing
your symptoms?

Good point…I guess my question is how did the engine run/plugs look before the head change?? If all was well prior to the change, then something changed with the new head….How do the combustion domes look in the new head, and irregularities?? And, like someone else mentioned, perhaps there is a water leak somewhere, but usually this causes the opposite issue, pistons domes cleaned up from water bath…..