Re: timing my 125's
Well, gentlemen: I just returned from a cruise to Nassau and the Bahamas. Weather did not cooperate so we were inside the ship almost all the time.
Hooyah: You did not do any damage by trying to time the engine with the plugs in. The reason timing is set retarded at cranking is because the magnets in the inside rim of the flywheel will exert a force on the moving components and slightly change the timing at higher RPM. The effect of slower cranking--within reason--would only change timing a degree or two at full throttle--negligible in terms of engine performance. Within reason is this: If the flywheel is not turning at about 350 RPM, not enough voltage will be generated to get spark. So, if you were getting spark, then you were turning fast enough to time the engine.
A high speed pop can be any number of thinks, from fuel to electrical so here is where you need to check one thing at a time and track it down. A high speed stop is almost always a fuel delivery problem although it can be ignition. SO: first check compression to see that the engine is producing power on all cylinders. Then put a timing light on each individual plug wire and see if , when the engine stops, it was still firing on each cylinder. Lastly, check the fuel delivery completely from tank to carbs. If you have crap in the fuel bowls, then the engine will start and idle well, but when you go to throttle up, the loose crap clogs the high speed jet and cuts off fuel, stalling the engine.
If you are hearing hissing noises from the electronics side of the engine, that, as noted in an above answer, would imply that one or more bypass covers are loose or the gaskets are broken. It could also mean that there is a hole or crack in the fuel pump impulse hose or you removed the hose from its nipple and did not put it back--thus: Low fuel flow and high speed stalling.
