Yanmar Whine

[salemsailor]

Hi, I have a Yanmar 2GM, (1987) on my Hunter.

Just fired it up for the season and after a few minutes it makes a high pitched whine, sort of like a 'fan' belt noise. I increased the RPM and the noise went away at the lower speed, but is still there at the higher speed. (noise increases in frequency as the RPMs increase too.)

I checked the belts and they look good (no bad wear) and the belt deflects about an inch and a half...maybe just a tad loose (from my recall) but not sloppy by any stretch.

Not sure if this is a belt problem or something else...didn't have time tonight to tighten/loosen the belts though.
Waterpump seems to be pumping nicely...(usual glub out the stern), fresh oil, properly winterized, etc, etc.

Thanks in advance for any help,

 

[Don S/V ILLusion]

I thin you are on to something with the belt - it should not deflect that much on that engine.

 

[salemsailor]

Thanks, Don. I'll adjust it tomorrow and then we'll know for sure.

 

[Don Crowther]

When i changed my belts this spring I didn't get the alt. belt tight enough. My belt was rubbing up against the guard on the alt. It to made a noise until it was tighten up. About .5 inch slack should do it.
I know how it feel to be so far away from your boat. I'm just 90 miles.
Good Luck
Don

 

[Warren Milberg]

You should be able to tell if the whine is coming from your alt or water pump belt by just running the engine in gear at higher rpms and opening the engine compartment and listening. You can do this in your slip with tightened dock lines or while underway if you have crew.

In addition to belts, I'd check the trans oil and make sure it is up to the right level. Finally, it could be a cutless bearing that is beginning to fail or your engine is out of alignment.