2008 Yamaha F115TLR Jerks at High RPM

ncseeter

Recruit
Joined
Oct 19, 2011
Messages
1
My 2008 Yamaha F115 has developed an extremely frustrating problem running at high RPMs. After I have been running at around 5500 RPMs or higher for some time , the RPMs quickly drop to 4500, and then the boat takes off like a scalded cat. The problem is intermittent. I can run several miles without it happening. I have also see it only drop RPMs by several hundred. The motor will run all day at lower RPM without issues.

I checked the 10 micron water separator and the gas looked good. There was no water and maybe 5 particles of some kind of sediment. I replaced it anyways. I checked the paper filter and it looked good as well. It has a full tank of fresh gas. I have used the boat all summer without issues. I always use Marine Stabil for E10. I have replaced spark plugs. I have checked all battery connections. I have checked all connections in the motor and everything looks good.

I'm still in the Yamaha Extended Warranty. I took it to the nearest Yamaha service center which happens to be a Cabela's. They saw the sudden RPM drop in the ECM history when they hooked it up to the computer. There were no error codes. At the same time they see a drop in battery voltage to 10.6V.

Has anybody see an F115 with similar behavior? Everything I read online makes me suspect fuel pressure, except for the fact that Cabela's service observed a voltage drop in the ECM history. Can someone confirm that battery voltage is monitored by the ECM and that they weren't mistaken?

Thanks in advance!
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,851
Re: 2008 Yamaha F115TLR Jerks at High RPM

yes it monitors battery voltage

Monitoring fuel pressures will say something, but will it tell if the pump is turning off due to low voltage or something else. I really do not know
 
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