Maybe someone out there can help me with this. Ive got a 2010 Yamaha F115 with 24 hrs on it. Under a load the engine develops a faint metallic ring or whistle above 5000 RPM. Initial diagnosis was the lower bushing on the driveshaft. greased bushing, greased again with volvo penta prop grease (the heavy stuff), changed bushing, even pulled the bushing out to try that. each time the sound would go away for a few minutes but come right back.
Thought maybe a vacuum leak. Checked IAC valve function, housing, and hose all looks ok. checked intake manifold for leaks with propane, no sign of problem there either. Even pulled off intake silencer and ran the boat. Problem persists. Cannot hear the whistle/ring with the cowling off, but might just be too faint to hear over engine noise (especially with intake silencer off).
I didnt see anything wrong with the tensioner pulley bearing besides being a little tight but still spins ok. greased it anyway with Yamaha spray silicone lube. Also hit the wiper seal at top of driveshaft and cam pulleys. Waiting my turn for a sea trial.
Can anyone think of any other reason why this engine is whistling/ringing...Please help. Im at my wits end.
Thought maybe a vacuum leak. Checked IAC valve function, housing, and hose all looks ok. checked intake manifold for leaks with propane, no sign of problem there either. Even pulled off intake silencer and ran the boat. Problem persists. Cannot hear the whistle/ring with the cowling off, but might just be too faint to hear over engine noise (especially with intake silencer off).
I didnt see anything wrong with the tensioner pulley bearing besides being a little tight but still spins ok. greased it anyway with Yamaha spray silicone lube. Also hit the wiper seal at top of driveshaft and cam pulleys. Waiting my turn for a sea trial.
Can anyone think of any other reason why this engine is whistling/ringing...Please help. Im at my wits end.