4.3 mercruiser alpha 1 - intermittent squeal on outdrive side of engine

[gscribner54]

I have a 1988 Regal with the original 4.3 engine and a '99 Alpha 1 outdrive (the previous owner reported he had to replace the original when it was stolen).

I have an intermittent squeal coming from the rear of the engine - from what I can figure, it is coming out of the area where the Alpha 1 drive shaft inserts into the engine coupling. I don't believe it is "telescoping" from another area of the engine. I have a little bit of a fan belt squeal, but I am able to get rid of that with a bar of soap!

Typically, the squeal does not occur until I run the engine up, into at least 1600-2000 rpm level (in the water with the forward gear engaged). If I take it further up, 2500-3000, the squeal goes away. Today, however, the sound was a little more disconcerting, and I thought I smelled a slight scent of something burning (could have been rubber, but I would not swear to it). So I headed back to the dock. I have been able to run the boat up to 3300 rpm, with no noise - however, I am running a 19 pitch prop with this V4.3 4 barrel (205 hp) and I don't believe I am getting the speed I should get.

I am suspecting the engine coupler - from pictures I see, it is triangular shaped and must have rubber embedded in it - I assume to provide some give and dampen the engine vibration you get in certain power ranges. Is this a reasonable diagnosis, and how big a pain is it to change this part out. Of course the outdrive has to come off - I am just praying the engine doesn't need to be pulled. Also, what happens if I keep running this thing - will it totally strip out at some point and not engage the engine to the outdrive?

 

[Don S]

Re: 4.3 mercruiser alpha 1 - intermittent squeal on outdrive side of engine

Pull the drive and check the gimbal bearing. Any roughness at all will make noise at higher rpm.

While you have the drive off, check the alignement and look at the splines on the coupler. And make sure they have grease.

 

[gscribner54]

Re: 4.3 mercruiser alpha 1 - intermittent squeal on outdrive side of engine

That probably is worth doing - heck of alot easier than pulling the engine. Any particular way to check the gimble bearing - anything to look for in particular. Looseness or wobble? Would the splines, which go into the coupler, show increased wear if the gimble has problems?

Also, if I do have a bad engine coupler - what is the worse that can happen (besides the noise) - will it finally strip totally out and leave me stuck. I thought of just running the boat to the end of the season - but also don't want to do permanent damage. I'll certainly pull the outdrive - that is cheap and fairly easy.



Pull the drive and check the gimbal bearing. Any roughness at all will make noise at higher rpm.

While you have the drive off, check the alignement and look at the splines on the coupler. And make sure they have grease.[/quote]

 

[Don S]

Re: 4.3 mercruiser alpha 1 - intermittent squeal on outdrive side of engine

The worst that can happen to the coupler is that it strips out. Happens all the time due to lack of maintenance (grease and good alignment). Not a big deal, they only cost about $350 and you have to pull the engine to replace it.

 

[gscribner54]

Re: 4.3 mercruiser alpha 1 - intermittent squeal on outdrive side of engine

Thanks Don - hope it is the gimbal bearing - I pulled the outdrive last year and did the impeller install - a little easier than muscling out the engine. I am a little concerned that the grease is running low, although I pumped grease into the fittings and greased up the outdrive drive shaft before reinstalling it. Probably need to do it again. Might be worth the cost of the gasket just to look. If the bearing has a problem, anything in particular to look for? - I guess just run your fingers on it to check for the roughness you mentioned. I assume if it is rough, it has to be pulled and replaced - no fixin that.

 

[Don S]

Re: 4.3 mercruiser alpha 1 - intermittent squeal on outdrive side of engine

I guess just run your fingers on it to check for the roughness you mentioned.

Geeeeeezzzzzzzzzzz, You don't feel the surface of the bearing for roughness with your fingers, you turn the inner race of the bearing with your fingers and feel if there is roughness in the bearing itself.

 

[mcleaves]

Re: 4.3 mercruiser alpha 1 - intermittent squeal on outdrive side of engine

This just made my night..

M

 

[gscribner54]

Re: 4.3 mercruiser alpha 1 - intermittent squeal on outdrive side of engine

That shows you how many times I have checked out a gimbal bearing - absolutely none!. I assumed incorrectly that this was a fixed polished ring of sorts - well I stand corrected. By the way, I ran the darn engine tonight (on the trailer) - could not get that noise to come back for all it was worth. Moved the steering wheel around to check out the "u-joint" theory. No change - no noise. Very frustrating. I may drop it back in the water on Saturday just so I can isolate the exact pattern of occurence - how many rpm's, etc. If the bearing is gone, it is gone - and if the coupler is going to totally fail, well I have a reserve engine (and unlimited towing).

I made an appointment with a mechanic I know is good - but I think I am wasting my time unless I can drop in the water and do an in-water test with him. On dry land, it appears to behave itself.

You know, I like mechanical systems that absolutely fail - not whimper and then die.