Re: 93 jazz 90hp sj, shuts off while on plane
Shutting off randomly could be a number of things. A short, failing electrical components, fuel delivery or some other issue. I'll note a couple of common issues here, but there are numerous threads under this forum for similar situations. Are there any other symptoms that you noticed when it dies? Does it sputter/miss prior to shutting down? If you look in the engine compartment, can you smell fuel? Can you see fuel dripping from the sound attenuator/carbs?
If the engine just shut down immediately the kill circuit should be checked for faulty switches (key switch, kill switch). Also, look for pinched, bare, or loose/corroded connections. There are more details (such as isolating the kill circuit) availble. You should get a manual for your model. Most will provide troubleshooting guides.
If the engine seems to 'starve out' for fuel when it dies, I would check the clear vent tubes on the Carburetors. These are notorious for clogging and preventing the floats from functioning properly. I was able to visually see 'reddish sludge' in the fittings/hoses on my setup. Clean the fittings/hoses well, replace hoses if necessary. It may be necessary to disassemble the carbs to fully clean...Rebuild if necessary. The floats may also need adjusting to be certain they are allowing enough fuel in at higher speeds/rpm's. The vent tubes are the yellowish lines here:
For starting, I would check the carburetor synchronization. This is a bar that connects the carburetors together (in the picture above, the bar to the left of the yellowish hoses). The best way is to take the sound attenuator off and look down the throat of the carbs. At nuetral, all 3 butterflies should be completely closed. They need to be completely closed to provide the vacuum necessary for starting. At wide open throttle, the butterflies should be completely flat. There may be a mark on the "L" connector for the synch-bar shown here if you want to try adjusting without pulling the sound attenuator (the line matches the butterfly position):
I'll add that the black stator is known for cascading failures. You may want to test per the instructions in the sticky at the top of this forum.
