Engine Squeal?

[Kevinbeck1]

Maybe someone has an ideal about this?
I have a 1998 Larson with a 3.0L Volvo Cobra SX I/O 4 cyl engine. When you start the boat there is a loud squeal that gets even noisier when the throttle is pushed down. Eventually the squeal goes away after a few minutes of operation. Something a bit unusual, when the boat is in operation, if you hit the trim button up or down at a low speed, the squeal comes back and then goes away the minute you take your finger off the trim. I have had a few people tell me that it is the circulator pump that is causing the squeal, I have replaced the raw water pump last year so I know thats not it. My father thinks it may be a belt issue but, it sounds way too loud to me, sounds like a bad bering somewhere. Any thoughts would be appreciated.
Thanks for your time.

 

[IVAZ]

Re: Engine Squeal?

Not knowing exactly what the squeal sounds like I would say check the belts.
It?s common for them to squeal at start up or when extra load gets put on them.
Try to pin point if it?s in the front or back of the engine if the belts are fine. If it?s in the back it could be the coupler.

EDIT: It?s common for them to squeal when they are not adjusted properly or have stretched.

 

[frustratedboater]

Re: Engine Squeal?

I immedialety thought of the coupler as contributing to the sound.

 

[Kevinbeck1]

Re: Engine Squeal?

Not sure I even know what the coupler is, the squeal is hard to pinpoint because it is extremely loud but I will investigate when the weather clears up. Is the coupler something that is difficult to replace or work on?
Thanks very much for your replies guys.

 

[IVAZ]

Re: Engine Squeal?

The coupler is in the back of the engine. You would have to pull the engine out to replace it.
Check everything up front first before assuming worst case scenario.
Good luck.

EDIT:
For your info I added a pic of a coupler. The yoke connects to the U joints in the drive. The pic is from the iboats store.

 

[dontask]

Re: Engine Squeal?

Have you thought about running the engine temporarily with the belt removed to see if it still makes the noise? Yes, you can run it for a very short period of time. The temp gauge will not reflect the engine block temp since the water is not circulating (so don't rely on it). If the squeal is not there any more you know which direction to go.

 

[capecodder116]

Re: Engine Squeal?

Just my two cents here...it sounds like you have a loose belt...check the tension on all the belts 1/2 way between each pulley...should have approx. 1/2" deflection. Also, do you see any "black dust" which would be a belt deteriorating or do you smell rubber..??

 

[z284u2try]

Re: Engine Squeal?

I had a squeal coming and going from a plastic power steering pulley. the pulley ended up breaking and merc had a service call to replace the pully with a steel one.