Re: 1972 65 evinrude triumph electric shift lower unit problem
Reving in neutral is a NO NO! The engine is in what could be called a free wheeling mode with nothing to keep it in check. It's very possible to encounter a runaway engine, which by the time you figured out how to stop it (seconds even), there would be connecting rods flying out the side of the engine. Example.... a 4 cylinder engine, running on 2 cylinders will rev up very high in neutral.
The propshaft comes loose? You'll need to explain that in detail as I don't see how that's possible.
Check the compression. What is it on all numbered cylinders?
With the spark plugs removed, the spark should jump a 1/4" gap on that model with a strong blue lightning like flame. Does it?
If the compression and spark are as they should be, and the engine does not turn up the proper rpms in forward gear, in all probability the carburetors are fouled and will require cleaning and rebuilding with complete carburetor kits.