1997 Yamaha 50 hp 2 stroke issues - The Hull Truth

hdhntr · 07-19-2009, 08:10 PM

Two problems with a 1997 Yamaha 50 hp two stoke with about 850 hours on it:

1. Intermittent problem with ignition which goes completely dead. The motor will not turn over or start, and I can't raise or lower it the unit. My mechanic incorrectly diagnosed it as an ignition problem, replaced the ignition, but the problem returned immediately. This occurs when the motor is either cold or hot, no difference.

2. After long periods of running in a range from 2,000 - 2,500 rpm, the motor begins to bog down. If I try to apply full throttle, it completely bogs down. However, it recovers immediately after I put it in neutral.

Thanks for any pointers, especially on number 1!

A1 Outboard · 07-20-2009, 06:32 AM

Check the battery cables for loose ends or breaks. Clean and check for tightness the cable connections at the battery and the engine. When the problem happens check the voltage at the engine, it should be within .5 volts of the battery. A skilled tech can run a voltage drop test on the electrical system. You may find the problem in this area. The fuel system may be the bogging problem. Run a vacuum and pressure check on the fuel system. Leave the fuel pressure in place to see if the pressure drops when the bog occurs. Be sure to check the fuel tank vent for plugging.