I know there are already some threads on here about modifying 20-35hp outboards. Just thought I would start a new one.
Here are some pics of a Johnson/Evinrude 3 cylinder 25/35hp I am modifying. Mine is a 25hp block. I hope to find a 35hp. I am starting with shortening the midsection 3-3/4”. It was a little trickier to cut down than the J/E 31.8 cu.in. towers I have cut down. The exhaust pipe and water passage are cast in on the triples. I haven’t yet figured out how to handle the water yet. I want the tower to look manufactured, so an external water pipe is out of the question.
The new motor will be run on my 11’ runabout. The current motor is a J/E 31.8 cu.in., bored 0.040” with wiseco pistons and a milled head, making 160psi. It runs 49+ mph. I still have some tweaking to do with that motor. Hoping to run 50+ mph next summer.
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