mercruiser alpha one gen 1 upper gear tapered bearing

[Daithiog]

Looking for some help .
Just received a new bearing, correct part number 31-32573A 1 but the old bearing is a wider bearing. Inner bearing diameter is also different. Any help on this would be greatly appreciated.

 

[Bt Doctur]

you should have got the correct race at the same time

 

[Daithiog]

Thanks for the reply, I have the race also but its a different size bearing to the original one which I have not removed from the shaft as you can see in the pictures. Is it possible that its a different size shaft or the wrong bearing is in the right box!!!!!

 

[achris]

The bearing you specified is for the 1.50:1 drive ratio. If you have a different ratio, it's a different bearing.

How about a bit more information that 'Alpha one gen1'? Let's start with a year, and the engine this drive is behind. If you have the serial number, all the better. Also, what is the drive overall ratio...

Chris.........

 

[Daithiog]

Hi Chris,Thank for the reply.
The serial number for the stern drive is
OB 891094

 

[Daithiog]

Hi Chris,Thanks for the reply.
The serial number for the stern drive is
OB 891094
I am very limited to the information I have on it, I am a mechanic myself but never refurbed a stern drive.
I have maybe takin things for granted when ordering parts when not knowing exactly what I have.

 

[Yegboats]

1987 drv: 0b891094 5010198as mercruiser alpha 1.98:1

31-35990a 1
timken cone 89449
timken cup 89410

 

[Daithiog]

Cheers Chris, you have made my day. Removed the race today and was shimmed underneath but no cut out for the oil in the shim.....
I presume my topcover bearing will be different also .
really appreciate your information.

Thanks so much

 

[achris]

With a ratio of 1.98:1, it means the engine is a 2.5 or 3litre GM 4 cylinder.

The top bearing is the same regardless of ratio. 31-61100A1.

I hope you have the shim and preload tools, and the (correct FACTORY) manual that tell you how to set it up. If you don't check and asdjust the shims and preloads, the drive will be noisy and will fail prematurely...

Chris......

 

[Daithiog]

I have no manual but will order one. Getting out the race was a nightmare on its own (upper case was seized )which I will measure the shims in the morn. Just worried about putting the new race in and if my backlash is wrong getting it back out.
thanks again for the info

 

[achris]

For a R, MR or Alpha One drive, you'll need Merc manual #6 (https://www.mercruiserparts.com/129342-sm-mc-alpha-83-90). Don't bother with the aftermarket ones (seloc, clymer) unless you need paper towels. (lots of errors and missing information)...

You're working on an Alpha One.

Chris......

 

[Daithiog]

Hi all,
i am struggling to get a mercruiser alpha 1 gen 1 new pre load washer and lock nut for the upper gear case here in Ireland or the Uk.
I presume this is not a re usable part , well the washer any way ??????

 

[achris]

Very very 'standard' parts. Any Merc dealer should have them, or be able to get them in a couple of days.

Part numbers...
Washer is 12-45810
Nut is 11-22339

It's the same for the Gen II drives... So those numbers are still the current parts.

Chris.........

 

[Daithiog]

Cheers Chris,
Had the get them sent from the US but have spares now for a back up ( hopefully won't need them for a while)
Type of grease for the new bearings?,I know it may sound like a silly question. Manual says 2-4-C just wanna make sure that will be correct and not react when I fill with gear oil.

 

[achris]

Don't use grease! Use gear oil.

Chris..........

 

[Daithiog]

Thanks so much for your help,
Dave