Belt Squeals with Trim Adjust - 2005 3.0L SX

H2O DVL

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Now I know what you're thinking, the belt is loose, but it's not that type of squeal. This is a "chirping" belt that is very distinct when the trim is fully down, but as the trim comes up (in increments) it lessens to the point when it's gone at about 1/2 trim. It's barely noticeable at idle, but as soon as you load it up it screams. Once on plane I trim up and it fades. Make a slight left or right and it's comes and goes.

So what could possibly be the connection between the trim angle / engine load and belt squeal? I have a theory (and I don't like it) so I'm curious what others think or have maybe seen. The boat is an '05 Glastron SX 175 with the 3.0 & SX outdrive.
 

Scott Danforth

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Squealing belts is a loose belt.

Could be bad alternator bearings, however there is no correlation between trim and belt squealing.

Try running the motor without the belt ( don't run for more than 20 seconds)

If the chirping is still present, pull your drive and inspect the u joints and gimble bearing
 

Shooterdustin

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Hey,

I am not an expert, but my alternator was squealing when I trimmed up or down. It was explained to me that alternators will sometimes squeal when under load. If the belt is tight and all the pulleys are aligned then it is probably the bearings in the alternator like Scott mentioned in the above post. You could have it rebuilt or just buy a new one, I don't think they are that much.

Dustin
 

H2O DVL

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Thanks for the ideas so far. I'm new to I/O's, but not boating, and certainly not engines. I know it's not a bearing or belt issue since applying a dressing to the belt keeps it completely quiet for a short period of time. Something is forcing one of the pulleys out of alignment when the trim is completely down, but lessens as the outdrive is raised or the load is reduced to an idle. I get the alternator loading scenario, but it doesn't stop when the trim motor stops (unless of course it's above 1/2 trimmed).

My theory; there are obviously splines on the outdrive shaft to allow for a slight change in length during different trim levels, and I'm wondering if those splines are badly rusted and as the drive loads up it's literally pushing so hard on the crankshaft (from the back) that it's forcing it forward, throwing the crank pulley out of alignment. I've seen this happen in the automotive world and take out the thrust bearings in the bottom end. Just wondering if the same possibility could exist in the marine world, or if anyone has come across it...
 

dypcdiver

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Belts wear and bottom out in the "V" and squeal. I suggest you replace the belt before looking any further.
 

bruceb58

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My theory; there are obviously splines on the outdrive shaft to allow for a slight change in length during different trim levels, and I'm wondering if those splines are badly rusted and as the drive loads up it's literally pushing so hard on the crankshaft (from the back) that it's forcing it forward, throwing the crank pulley out of alignment. I've seen this happen in the automotive world and take out the thrust bearings in the bottom end. Just wondering if the same possibility could exist in the marine world, or if anyone has come across it...
NO!

It's the alternator belt squealing because of the load on the alternator. As a test, take the excite wire of the alternator and the squealing will stop.

Replace the belt...dressing is a waste of time.
 

H2O DVL

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NO!

It's the alternator belt squealing because of the load on the alternator. As a test, take the excite wire of the alternator and the squealing will stop.

Replace the belt...dressing is a waste of time.

If this were the case the squeal would stop when the load on the alternator stops, and it doesn't. If the trim is fully down (and I'm off the trim switch) the squeal is at its worst. Bring it up a little (about 3/4 trim down) and release, the squeal lessens. Raise it to about 1/2 and release and the squeal is gone. Trust me when I say it's related to the angle and load on the outdrive. The dressing was just to confirm it was belt related and not a pulley or bearing.

It's obviously difficult to watch the pulleys when I'm at the helm and the engine hatch down. I'll get the wife to pilot next time out so I can have a closer look at the engine bay...
 

bruceb58

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Put on a new belt. If it still squeals, you should be looking at replacing the bearings in your alternator.
 
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H2O DVL

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Belts wear and bottom out in the "V" and squeal. I suggest you replace the belt before looking any further.

That's a good point, but it's not a V belt. It's a serp belt, and the belt is in good shape.
 

H2O DVL

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So, just to follow up on this issue (I hate searching and reading posts that have no conclusion), I have confirmed that is is belt squeal and NOT a bearing or pulley issue, and that the crankshaft IS walking fore & aft throwing the crank pulley out of alignment and causing the squeal. Spec for crank end play is .002" - .006". I measured at least .020".

So now to determine if the drive splines are rusted and/or corroded and are causing the "push" on the crank, as I suspect they are. I'll be in the water this weekend so I can drop the trim all the way down and see if the crank still exhibits play. Stay tuned sports fans...
 

bruceb58

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If you really think that's the issue, why not pull the drive? Takes around 20 minutes.
 

H2O DVL

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That's the plan, but next week. I can't put the drive all the way down/in when it's on the trailer (without jacking the trailer way up) and since I want to use the boat this weekend anyway I'll just do the end-play test when it's in the water. If there's still end-play in the water with the drive down then I know it isn't the drive pushing on the crank and there's no point in pulling it.
 

H2O DVL

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I just got the boat this year. It was on my list of things to do this fall before putting it away for the winter. I guess I should have said there's no point in pulling it to look for a problem.
 

dypcdiver

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I can't help feeling that your problem is the load put on the alternator by the trim pump is causing the belt to slip a little and cause the squeal.
 

H2O DVL

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I can't help feeling that your problem is the load put on the alternator by the trim pump is causing the belt to slip a little and cause the squeal.

If this were the case the squeal would stop when the trim pump does, and it does not.

So after checking the crankshaft endplay with the boat in the water and the drive all the way down/in, the endplay still exists. So, this wipes out my theory of the outdrive splines binding and pushing on the crank throwing the pulley out of alignment. Back to the drawing board...

I did replace the belt. There were a couple questionable portions on the belt where the ribs/grooves showed more wear. I'm sure this will eliminate the "chirp" but it still doesn't explain why it came and went with the angle/load on the outdrive. Strange...
 

Lunkerman

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The only chirping noise I had was thought to be from the belt driven components. It actually ended up being the bearing in the seawater pump. Not sure but changing the angle of the outdrive could indicate the supply hose from the outdrive to seawater pump could be getting pinched.
 
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H2O DVL

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The only chirping noise I had was thought to be from the belt driven components. It actually ended up being the bearing in the seawater pump. Not sure but changing the angle of the outdrive could indicate the supply hose from the outdrive to seawater pump could be getting pinched.

Interesting thought, but putting a dressing on the belt temporarily quenched the noise.
 

H2O DVL

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Well, the saga, read; squealing continues. The new belt made things nice and quite for about 1 day, and then the chirp/squeak returned. Not quite as loud or obvious as the old belt, but it's there, and is still outrdrive/trim related. I've pulled the plug on the Alt., no difference. I've applied a dressing to the belt while it's idling and it's instantly quiet, (so it's NOT a bearing) temporarily of course.

I'm still leaning towards something in the drive pushing forward when it's under load, and is either pushing the crank forward (because of the end play) or has created the end play by pushing on the crank/thrust bearings.

I have a few more boating weekends planned for the season, so I think I'll just monitor things and then pull the drive before I store it for the winter.
 

H2O DVL

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So, just to put some context to this ongoing issue, I've taken a video to show (and hear) what I'm referring to. I'm winterizing the boat as we speak, so I took this vid while I was at it. I'm pulling and pushing on the raw water pump and if you look closely you can see the crank walking in and out, and the chirp coming and going.

I know the crank shouldn't walk quite that much, but, I'm going to put a new tensioner on it in the spring and see if that resolves things. Now to figure out why it's trim angle related....
 
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