Re: RDE-18 powerhead to exhaust plate/gaskets

[William Jatzek]

I have a 1956 Johnson 30 HP. It’s my favorite big twin. I went over it about seven years ago with the help and direction of a man who specialized in mid 1950’s OMC. He told me to remove and not use the baffle plate just install the power head back on the leg with one gasket. He said he had a OMC factory bulletin that said to remove the baffle plate. They did not use it on the 1955 big twin or the 1957 it was probably something they experimented with then decided to eliminate it. I did what he recommended and discarded the baffle plate. I have used the engine all those years and never had a problem with it. It never overheats anywhere on lower leg.There are video’s of my engine and boat on You tube if you want to look ( 1956 Lyman and 1956 Johnson ) Cleveland Ohio. Also he told me of another factory bulletin modification for the 1955 Big Twin 25 HP. it was in regard to the engine getting enough air to the carburetor if you look at your front bottom pan casting where your electric start wires come into the engine you will see a 2 inch hole right in the middle. The 1955 engine only had a 1/4 inch hole there with the new design cowl of the 1955 and the rubber gasket the engine could not get enough air. The bulletin said to drill out the 1/4 inch hole to 2 inch to let the engine breath. I also have this engine and it was a dog on top end compared to the 30HP.It had the small hole I never would have known why it was slower if he would not of told me about it. You live and learn. Regards Bill,