1988 130 hp Yamaha alarms at high rpm

[Shrek1]

I just bought this motor from a Yamaha dealer. I have been reading all the alarming issues I could find, but none seem to be my problem. The dealer also installed the digital gauges. The motor runs fine up to about 3400 rpm. The alarm sounds, but the engine does not die back to 2000 rpm per the book. I usually back the throttle back to a idle, until the alarm goes off. No over temp alarm, and the pee stream is cool to the touch. However, the engine seems to start missing, or running rough. When the alarm goes off, the engine seems to run smooth again. It did it 3 times tonight, all with the same sequence, alarm, rough idle, then it smooths out. we ran for almost a hour at 3000 rpm, with no problem. The oil reservoir is full. The Gas is fresh and I replaced the primer bulb. There are no air leaks in the gas line. Any Ideas? the dealer is not in over the weekend.

 

[Ray Neudecker]

Re: 1988 130 hp Yamaha alarms at high rpm

Were there any visual indicators on the tach when this happened?

 

[JUSTINTIME]

Re: 1988 130 hp Yamaha alarms at high rpm

yamaha has 2 warnings

oil
overheat

iy is one of those

 

[Shrek1]

Re: 1988 130 hp Yamaha alarms at high rpm

no indications on the tach for temperature at all. oil level is full. The engine does not automatically idle back to 2000 rpms, I do that manually. I stuck my hand behind the engine right after it alarmed, and I would say the temp of the water may be around 140 to 150 degrees, not scalding, or overly hot. I took it out again today from 11 am til 8:30pm and as long as I kept the rpms under 3000, no alarms all day. I pushed it once to 3100, and it alarmed. And again, the ilde became rough/missing when I backed the throttle down, then, once the idle smoothes out, the alarm goes off. or when the alarm goes off, the idle smoothes out.

 

[Silvertip]

Re: 1988 130 hp Yamaha alarms at high rpm

Sounds like overheat due to a stuck thermostat. Try replacing it. It could also be a defective overtemp sensor.