2001 F25 Yamaha (Merc) Checked the valves at fif****, 200, 300 and 400 hours. Adjustment was only needed at the fif**** hour check.
Now the engine has 550 hours and here is what happens. starts and runs ok. after the engine reaches normal operating temps, at low RPMS, say 1700 to 2800 RPM I hear what I think is the noise of loose valves. Above 2800 RPM I don't hear the noise because it gets masked by the roar of the engine.Its bothersome because the noise was absent till 3 things changed:
1. The engine now operates in South Florida instead of Northern CA.
2. It now uses 90 octane Non-Ethanol gas instead of 87 octane ethanol gas.
3. It now uses 20W40 Yamalube instead of 10W30 yamalube oil.
I suspect the valves finally are loose and need to be adjusted and the question is this:
Do you guys think one of the three changes above is causing the noise and not loose valves? and what are the dangers of operating the engine with loose valves? I can't pull the boat for a while and I do want to use it in the meantime.
Now the engine has 550 hours and here is what happens. starts and runs ok. after the engine reaches normal operating temps, at low RPMS, say 1700 to 2800 RPM I hear what I think is the noise of loose valves. Above 2800 RPM I don't hear the noise because it gets masked by the roar of the engine.Its bothersome because the noise was absent till 3 things changed:
1. The engine now operates in South Florida instead of Northern CA.
2. It now uses 90 octane Non-Ethanol gas instead of 87 octane ethanol gas.
3. It now uses 20W40 Yamalube instead of 10W30 yamalube oil.
I suspect the valves finally are loose and need to be adjusted and the question is this:
Do you guys think one of the three changes above is causing the noise and not loose valves? and what are the dangers of operating the engine with loose valves? I can't pull the boat for a while and I do want to use it in the meantime.
Comment