Squeal during trim

[PROC]

I have a 2001 2900 SCR single 7.4MPI Bravo III. When I get on plane and start to trim the outdrive, there is a point where I get an awful squeal out of the engine compartment for a few seconds. Seems like it's getting worse since the beginning of the year. Any ideas?

Thanks!

Bryan

[Phillbo]

Does it also happen if you have the motor off when you cycle the trim up or down?

[PROC]

No, only when I hit plane, cross about 4000 RPM, and start trimming up the outdrive..

[mcoffey]

Sounds like loose alternator belt to me. Trim motor puts a big load on battery and alternator and that can cause the belt to slip if a bit loose.

[pascavone]

Sounds like your outdrive u-joints and engine coupler needs a shot of grease.

They are flexing when you trim.

Call a mobile marina mechanic for a full lube job, steering too.

[PROC]

Thanks guys! I have the boat out of the water right now so I'll start with the lube job and go from there!

[ss3964spd]

I was unaware that the coupler can be greased. The u-joints cannot be greased without pulling the drive, and even then only if they have grease fittings. The only thing that I know can be greased is the gimbal bearing.

Bryan, see if you can replicate the symptom. If it happens everytime you trim the drive up, see if it does it when you trim it back down at the same RPM. You can also try trimming the drive up/down while at idle to see if you can cause it to squeal. If so I'm kinda liking the belt idea.

[pascavone]

whats your top speed with your boat, at what RPM?

just wondering.

[PROC]

Now that I'm thinking more about it, it will squeal even if I start trimming the tabs first. It's like a certain angle of the boat when around 4000RPM causes it to make noise. It only does it when I'm getting on plane. Once I back it down to cruising speed, no more noise. No noise trimming at idle, cruising speed, or full speed. Only hole shot. Weird...

[PROC]

About 32mph @ 4600RPM

[mcoffey]

U-joints cannot be greased unless they were replaced with an aftermarket brand. Stock Mercruiser joints are permalube style with no grease fitting. Also, if the Gimbal has been replaced with a genuine Mercruiser replacement, no greasing it either. The new ones come without a hole and a plug to block off the greas fitting hole on the outdrive.

I guess the $100 question is, does it only make noise while trim button is engaged and then stops once you let go of button? If yes, look at the belt.
If it starts making noise and the noise continues after releasing the button, could gimbal or u-joints as pascavone mentioned.

BTW-Aftermarket u-joints and Gimbal (like from Sierra) do have grease fittings so you can grease them if you have them. The Gimbal is greased by fitting on outdrive and you have to pull off the drive for the u-joints.

[pascavone]

that what i get with a 2000, 34mph @ 4800 rpm

[PROC]

Thanks everyone! I'll let you know how it goes.

Bryan

[AlwaysSober]

Originally Posted by pascavone

Sounds like your outdrive u-joints and engine coupler needs a shot of grease.

They are flexing when you trim.

Call a mobile marina mechanic for a full lube job, steering too.

My coupler grease fitting is a PITA to get to. Grease gun needs the hose and swivel to get it on there. One of those times when I wish my forearm had another elbow.