Volvo Sx Whine noise

[mikebc]

Hey,<br /> The new boat runs great, but I hear a whine after I run it hard for a while and then throttle back. It sounds like a drive noise, but I'm only guessing. It goes away if I idle down to under 2000 rpms, but will return again if I open it up for a minute and back the throttle down to 1/2 or so. It's a 2001 Volvo SX with a 4.3 carb in a 19' larson. Oh, and trim position doesn't seem to make a difference. I have it going back in for a new throttle cable next week anyways, any clues on the noise or is it normal? It sounds a touch louder than the engine, but the engine is super quiet. Thanks again guys!

 

[mikebc]

Re: Volvo Sx Whine noise

Hummm, could it be a alternator going bad? The volts read low, but it keeps starting and running all of my electronics. I'll to a volt meter on it today and see what voltages are running and shut off. Any idea if these are rebuildable, and how much the rebuild part kit is?

 

[mikebc]

Re: Volvo Sx Whine noise

Well,<br /> It has 12.3 volts with the engine off and 13.1 with the engine running. I didn't hear the noise today, but Monday or Tuesday I'll run it hard again and check the volts. Could the bearings in it be going out and it still work, but make noise?

 

[mikebc]

Re: Volvo Sx Whine noise

Any ideas,<br />I've read that the fuel pump can do this, any ideas??

 

[mikebc]

Re: Volvo Sx Whine noise

Hey!! I fixed it. I ordered a new prop, the one the dealer said was for the boat. The new one was 1/4 ~ 1/2 less in diameter. Guess what, the noise is gone. Has anyone ever heard of this?

 

[mikebc]

Re: Volvo Sx Whine noise

Well, I'm glad this fixed the problem, but has anyone ever had this issue? I wouldn't mind the larger diameter prop, the boat went a little faster with the old prop, at the same rpm's.

 

[Sooner44]

Re: Volvo Sx Whine noise

Mike,<br /><br />Sounds like you garnered a lot of input here <br /><br />Thanks for sharing you experience with us, I learn something every day<br /><br />Sooner