Top cover bearing for Mercruiser 4.3?

[jimmyc607]

A couple weeks ago I had my boat out and everthing was running well until I made it back to the loading dock to load the boat. The boat stalled on me and when I attempted to restart it was hard to crank over. It did start but then I heard a bad grinding clunking noise coming from the outdrive.

Got the boat home and just recently had time to pull the outdrive to investigate. I found the problem and thankfully it wasn't anything engine related or too expensive however i'm wondering if anyone here can tell me which bearing I need and where to find it?

The bearing under the top cover of the outdrive is destroyed. I got lucky and there was no damage to any of the gears. From what I understand it's called a top cover bearing?

The boat/motor is a 1990 Mercruiser 4.3LX with Alpha 1 outdrive. Any help is greatly appreciated!

 

[ktbarrentine]

Re: Top cover bearing for Mercruiser 4.3?

Please post the ser number of the O/D.... from year vintage it is an Alpha-1, but ser number will confirm and then you can start looking for the right parts. Now, having said that, what did your oil look like when you drained it, and how much came out, 'cuase it sounds like there wasn't enough in there to lube the bearing, or the bearing somehow developed a fault of its own. In any event, you've most likely gots bits/pieces of destroyed bearing all over the place, and most likely in the lower gears.:facepalm: Can you provide more details and maybe post some photos?

 

[Don S]

Re: Top cover bearing for Mercruiser 4.3?

If you can read the bearing number on the old bearing and race, you can find them at about any bearing company.

 

[jimmyc607]

Re: Top cover bearing for Mercruiser 4.3?

Thanks for the responses. Where on the outdrive would I find the serial number located? The fluid in the outdrive was just replaced at the beginning of the season by me when I got the boat. It looked to be in good shape then and no metal shaving etc. I drained it before pulling the outdrive a few days ago and the fluid still looked good with no metal anywhere. I even ran a good amount through a paint filter to make sure and it was clear.

The bearing looks like it did not have enough lubrication at some point and it just ended up failing. It must have gotten extremely hot because a few of the bearing rollers seized onto the inside of the bearing. I checked visually for any metal and/or damage to the gears and do not see anything.

If I need to I have no problem taking the outdrive to a marina but thought a simple bearing replacement could be done by myself. As far as the bearing goes there's no chance in reading anything on it, it's pretty rusty and destroyed

 

[FreeBeeTony]

Re: Top cover bearing for Mercruiser 4.3?

it's pretty rusty and destroyed

Rusty would make me think water was involved somewhere along the line..........

Do you have a remote resevoir?

 

[jimmyc607]

Re: Top cover bearing for Mercruiser 4.3?

Yup I think at some point there must have been some water in there to cause the rust. Everything else looks clean and in perfect condition besides the bearing though. When I replace I planned on doing all new gaskets and seals of course.

 

[jimmyc607]

Re: Top cover bearing for Mercruiser 4.3?

Found the serial number I think? The Mercruiser tag located on the transom housing reads Ser No. 0D347110, does this help at all?

 

[Don S]

Re: Top cover bearing for Mercruiser 4.3?

You will need to measure the OD of the bearing cup to find the right bearing.

The Mercruiser bearing numbers are as follows.

1.94" OD - PN 31-61100A1
1.78" OD - PN 31-32575T1