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Tan
Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 10642
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
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I have a 1988 Ebbtide with a magnum 350 Mercruiser and I've

Customer Question

I have a 1988 Ebbtide with a magnum 350 Mercruiser and I've been noticing a noise when I have the trim too high or low, or when I turn. I've found a plug at the top of the unit marked Vent, and one at the bottom for drain. Where do I check the oil level in the lower unit? This noise sounds like something's binding a little, or something. I'd appreciate any info you might have. I just bought the boat this spring and want to take care of it.
Sincerely, Paul
Submitted: 1 year ago.
Category: Boat
Expert:  Tan replied 1 year ago.

Hello. My name is Tan.

Noise coming from the drive are when trimmed or turning is a failing gimbal bearing or u-joints failing. This cause by water intrusion into the u-joint bellows # ***** You will most likely find a hole in the u-joint bellows from age or something has punctured the bellows.

To determine if this is the issue inspect the u-joint bellows # ***** or pull the drive off. http://www.boats.net/parts/search/Merc2/Mercruiser/R-MR%20Alpha%20One%20%28Drive%29/6225577%20THRU%200D469858%20%281983-1990%29/parts.html

The repair is to remove the drive,u-joint bellows, gimbal bearing # ***** and the u-joints. Now depending on haw bad the water intrusion is the yoke and seal may have to be replaced also. http://www.boats.net/parts/search/Merc2/Mercruiser/R-MR%20Alpha%20One%20%28Drive%29/6225577%20THRU%200D469858%20%281983-1990%29/GIMBAL%20HOUSING%20SQUARE-SPLINED%20UPPER%20SWIVEL%20SHAFT/parts.html

This is a pretty big job and does require some special tools to do this job.

There is a grease fitting A to grease the gimbal bearing. Grease the fitting then start engine turn drive hard over to one side does the noise sound better? http://www.boatingwithtr.com/Members/images/GimbalBearingGreaseFitting.gif

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