I have a 2006 Yamaha 150 4 stroke that keeps losing power and a constant alarm until you turn the motor off to reset. It was restarting fine and would run for 10-15 more minutes and then do it again. Took it to the shop and they cleaned the fuel injectors and fuel rail. they river tested it and said it was fine. Got it back today and went straight to the water. 15 minutes into the run the same problem. Stopped and restarted and then kept going so we could get our work done that we needed to. In a 4 hour trip this probably happened 6 or 7 times. Wasn’t a big deal since we have to stop every 5 to 10 minutes anyways but on the last time that we lost power and shut it off, it did not want to restart. sounded like a dead battery just barely turning over. flipped the switch to the other battery and same thing. Eventually got it running and made it back to the dock. With the fuel system having just been cleaned and this new problem with trying to start it, could it be the power pack? Is there a way to check if the power pack is going bad? Any other suggestions? The boat will be returning to the shop but wanted to get some suggestions on what might be happening from here.
Thermistor shutting the motor off is my guess. I bet the poppet valve is bad and its getting hot, especially if you are at idle or close to it.
My 2 cents.
Let us know what it turns out to be.
anytime you get a constant alarm with that motor, it should go into RPM reduction
thermistor doesn’t shut the motor OFF, just puts it into rpm reduction
sounds like its overheating
Least I was in the likely ballpark with the temp issue. Good to know what the thermistor does. When my poppet valve went bad, it would go constant alarm too, but would not restart till motor or more correctly thermistor cooled off, then it would fire right up.
Listen to Chris, he is always right.
Thanks for the ideas. I will let you know once the issue has been resolved.
driver, thanks for the vote of confidence, but I definitely am not ALWAYS right.
well trained, experienced, and practical, but wrong plenty of times, just ask my wife.
if the overheat sensor stopped your motor from restarting, you had another issue.