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!
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!