Alpha lower unit question

C

cfelton

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Nov 11, 2008
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I ordered a complete seal kit for my Alpha one lower unit thinking it needed a shift shaft bushing and seal. After pulling the lower unit off I found oil coming out from under the water pump. When I took the pump off I noticed about 1/16 of an inch play up and down and side to side, in the pinion (input) shaft. I can pull up on the shaft and the tapered bearing seats and the play goes away. Does it need reshiming? There was no metal in the oil and it ran smooth the last time I ran it. I hate to put new seals in it only to have them torn up again. Anybody have any ideas on how much play in the pinion shaft is normal?
 
Don S

Don S

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Re: Alpha lower unit question

First off lets find out what you really have.
77 Wellcraft w/170 Merc.
I assume this was repowerd with the 170 at some point as that motor was only used in 85 and 86 and would have an Alpha One if an 86.
Is this what you have?
 
C

cfelton

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Joined
Nov 11, 2008
Messages
11
Re: Alpha lower unit question

Yep, it was repowered with a 170 mercruiser and a alpha one outdrive around 85 or 86. I just bought it in 2006 and rebuilt the engine and gimble/transom assy. I was told the outdrive had just been rebuilt, but you know how that goes! The numbers on the upper drive are A348897 D. The serial number for the engine is A345238. I know that a 46-96148A waterpump kit fits the drive perfectly. I cant find any numbers on the lower unit but I know it does not have a pin sticking up on top of the input shaft. My buddys 86 model looks exactly like it except his has a pin on top of the input pinion shaft. Sorry I forgot to tell you. Thanks for your help!!
 
Don S

Don S

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62,321
Re: Alpha lower unit question

Great, the play in the shaft is normal. When the engine is running, the shaft pushes up against the bearing which holds the proper gear position.
You leak is from the lower raw water pump housing. The seals could be bad in the housing or the shaft could be bad. Maker sure the lower pump housing is in good shape too.
If run dry, the lower portion can warp and cause leaks.
From where you are describing the leak coming from, a worn out pump will cause an overheat and melt and warp the plastic pump housings. If you aren't sure, replace it all. Upper and lower, and NEVER run the engine without water to the outdrive.
 
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