I recently acquired a 1967 3hp Johnson folding outboard. It's in excellent cosmetic condition, however when I tested the motor I noticed the pistons were seized. Upon inspection of the cylinders I noticed spotty rust on the cylinder walls. I replaced the piston rings, the head gasket, and honed the cylinder walls. I also added new points and thoroughly cleaned the carb. When I checked the compression, I was disappointed to find that it was only about 50-60 psi. I attempted to start the motor with no luck. My question is, is 50-60 psi an acceptable compression for a motor with new rings and head gasket?
Also when I was examining the coils I noticed that one of the coil wires was loose and could be removed from the coil with ease. I replaced the wire and used silicone to seal it. My experience would say that spark is most likely the issue, but when I tested it on the side of the motor, the plug threw a decent looking spark (about 1/2 an inch and blue).
And the funny part is, I have a spare power head, but because the motor is "folding", the adaptor plate and the power head are a little different.
I'm an OK mechanic, but I can't seem to figure this one out.
Re: 1967 Johnson 3 hp "fold-up" (Trouble starting)
Thanks for the info! Based on what you said about the points/condensor, I think my next move might be swapping the entire ignition system from a spare 68' JW conventional shaft, for trouble shooting purposes. But in regards to compression, do you know if there's is a break-in period for new rings, or should it be 75+ immediatly following an overhaul?