cjbrill715
Regular Contributor
Hi guys, was running my 1956 30 hp Johnson (RD-18) In a 55 gallon drum today, and I pulled the plugs to see what color I was getting. The top plug was a nice golden brown with a little black, But the bottom plug was almost clean as a whistle. The compression reads around 120 psi top and bottom, but It does seem to have an issue idling down smoothly without cutting out. I can't find any exploded views of this motor, and I'm not too familiar with the anatomy of this motor. My question is, are these motors subject to water getting into cylinders if the head gaskets get bad?? It is running on both cylinders, but it seems a bit "tuggy/jerky" at lower rpms.