rumbling alpha gen 2 drive

S

steve930

New Member
Jan 27, 2011
31
u.k. south coast
Boat Info
220da
Engines
5.7/alpha 1 gen 11
After going on a longish cruise a couple of weeks ago (2hrs at 20-25 knots), I'm now hearing a rumbling/droning noise, You can hear the noise most at slow speeds. The noise is only evident when the drive is in gear (either forward or reverse) I'm guessing that the bearings in the lower half of the drive unit are getting noisy. Has anyone on here replaced these bearings themselves & how much of a job was it to do? I realise i'd have to buy several special tools to do the job
 
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Does the noise get louder if you turn the steering wheel? If so I would suggest gimbal bearing.
 
Give your gimble bearing a few shots of grease and see if its any different.
The bearing is spinning anytime the engine is running but, in gear it's under a load so may sound different.

Goodluck,

Mark.
 
Probably the gimbal bearing - when tearing it apart check u-joints while you're in there.
 
I will try the suggestions but the gimbal bearing was new at the start of 2012 season & I rre-packed it with grease at the start of this season.

the boat stays in the water till around Xmas, then I pull her out for a few months, so I can't do anything til then
 
steve930 said:
I will try the suggestions but the gimbal bearing was new at the start of 2012 season & I rre-packed it with grease at the start of this season.

the boat stays in the water till around Xmas, then I pull her out for a few months, so I can't do anything til then
Click to expand...

Misread - I see you said when "in gear" only, that steers away from the gimbal or u-joints.
Have you tried (with the engine off) just spinning the prop in neutral to feel anything loose or turning rough?
 
KC_Sundancer said:
Misread - I see you said when "in gear" only, that steers away from the gimbal or u-joints.
Have you tried (with the engine off) just spinning the prop in neutral to feel anything loose or turning rough?
Click to expand...

where the boat is still in the water, the prop stays mostly submerged when the leg is fully trimmed up. due to this I obviously can't get a "proper feel" to be able to make any judgement.

I just wanted to get an idea of the work/process involved in changing the bearings (if needed) from someone who's done it. there doesn't seem to be much info on the net.
 
quick update, been out for a cruise on her today. I was cruising at 25 knots & I started hearing a whining noise, this lasted for about 20 - 30 secs and as I was about to back off the throttle there was a BANG & the boat came to a standstill. there is no drive in forward or reverse!

whatever has broken has also wiped out the waterpump drive. I left the engine running whilst I lifted the engine cover just checking I wasn't taking on water, when I then went to shut down the engine I noticed the temp gauge was reading 180 & climbing.

I radioed the coastguard and got towed back into port. I've just finished getting the boat back on her mooring.

I think we can rule out the gimbal bearing being the cause of the noise!!
 
Any weird smells such as burnt rubber. Usually a coupler will make a bad smell when it fails.

When the bang happened did the engine stall or just freewheel?
 
no smells of rubber. the engine carried on running

there was no clunking or rattling noises, just a total loss of drive
 
Let us know once you haul it out and pull the drive. Doesn't sound good, your certain the prop hub is good and you didn't strike anything. That sure would be a miracle fix compared to a new out drive.

Was the water shallow? Sometimes growth or muck and vegetation can block the intakes.
 
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Total loss of drive with no noises and lack of pumping water has me guessing something in the top end of the outdrive itself broke. :huh:
 
yeah it could be, our even the shaft to the lower half of the leg/waterpump.
I don't think it's the main uj's broken otherwise I think youd hear some rattling or everything would lock up.

until I can pull the boat out the water, it's all guesswork. I'm not gonna pull her out til around December though
 
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