Power issue

[Zatarra]

Hi everyone,
Recently my boat experience is a loss of power when I first start out. The boat won't go over 40 miles an hour. if I turn it off and turn it back on again the problem resolves itself. Once I do this reset, the engine hums and sounds the way it should and I'm able to hit 50 plus miles an hour. I have a Yamaha 2009 limited s. Any ideas? Thinking it's electrical due to the fact that it goes away when I turn it off and turn it back on again.

 

[Beachbummer]

What are the RPMs when this happens?

Any unusual noises or vibrations? Any other symptoms?

 

[Zatarra]

They don't hum at the same frequency until I do the power off power on thing.

 

[Zatarra]

The RPMs are not in sync until I do the switch on switch off

 

[Beachbummer]

right, but do both engines reach max RPM of around 10,000 RPM?

Any chance you have some loose sealant around the jet tunnel that may end up like a long string in the water path causing interference with the water flow from time to time? Watch the MAX RPMs that the boat reaches when it happens next time to see if it's engine or pump. If one engines jumps way too early to 10,000+ RPMs there is something causing that pump to slip/cavitate which causes a loss of thrust.

 

[Gym]

I'm thinking plugs or coils. When was the last time the plugs were changed? Which engine shows the lowest RPM when you're only getting 40mph?

 

[Zatarra]

The plugs were just changed this season. The starboard engine will be up around 10,000 and the port like 8,000. What doesn't make sense is that it goes away once I restart it and they run at the same RPMs after restart. Beachbummer, I'll check next time but I think i do notice the port engine jump a bit when I throttle up and then it comes back down within a second or two. I think it does that even after I restart it.