Many years ago (like 20) I had bought various parts required for rebuilding my old 1956 30hp Johnson. This included a full gasket set, rings and a complete (alleged) 30hp powerhead. I knew one of the pistons was scored on my motor, hence the purchase of the extra powerhead. Somewhere between there and now I completely got side-tracked while indulging in other pursuits. A recent Craigslist old outboard impulse purchase (’59 18hp) and years later I’m bitten by the bug again and ready to dive in to finish what I started.
My first step was to get the pistons out of the core powerhead in preparation for the transplant. After pulling the pistons from the core motor I noticed that the wrist bearings had plain bearings – not rollers. Given this, it appears I really have a 25hp core.
So, the question is… Will they work? According to service information both have a 2 3/4″ bore & 2 7/8″ stroke. However, in the parts manuals they have different numbers 376794 for the 30hp and 375781 for a 25hp. Do any old outboard gurus out there know if these can interchange without major carnage or loss of power?
-
This topic was modified 2 years, 4 months ago by OB1.