Alpha One/Gen1 Bell Housing Shift Shaft Bushings

Rivergator

Petty Officer 1st Class
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May 7, 2013
Messages
224
I am having a big problem with the shift shaft bushing kit 23-805041A2. I purchased a high quality kit from SEI part #9D-106-24K. This kit is the right kit for my Alpha One/Gen1 drive so it says. I read a few reviews about this kit ( including different brands) and the biggest complaint is that the bottom bushing is way out of tolerance. When I got the SEI kit I tested it on my shift shaft and sure enough it is way too sloppy for a new bushing. This new bushing is as bad or worse than the old bushing and I am sure that the old bushing has been in the bell housing for quite a few years if not since 1988. I contacted SEI for clarification but I am still waiting for an answer. Maybe one of you can shed some light on this. Here are the measurements:
The shift shaft diameter as measured by me is .3705". The upper bushing inside measured is .3760" which seems reasonable. However the lower bushing is ridiculously sloppy at .3930". According to my Mercruiser Manual both bushings upper and lower have the same part number #23-814308 and therefore should have the same inside diameters, which of course makes sense, because the shaft's diameter is the same throughout its entire length. Also in my opinion, if the lower bearing has excessive play it will compromise the sealing ability of the upper bushing water seal. Are we talking about a manufacturing defect here or do I have the wrong lower bushing?
 

Kubaat3lover

Chief Petty Officer
Joined
Jun 6, 2019
Messages
443
I purchased a high quality kit from SEI part #9D-106-24K.
Oldboys from forum gonna kill You :))

Hope this helps:
MerCruiser p/n 23 - 805041A2 bell housing shift shaft seal upgrade kit. It is pressed into the bell housing on Pre-Alpha & Alpha One drives. It will also fit Gen II drives Serial # OF094775 and below.

The large diameter will extend into the exhaust cavity but will have no affect the exhaust. This upgrade kit now has 2 heavy duty seals installed compared to the one thin seal shown above.

The driver is not included with the kit.

The outside diameter of bushings is 5/8
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
That bottom bushing is always 'sloppy' it's meant to be so the housing can drain when the boat is out of the water... (Which is another reason why you need to leave the drive in the DOWN position when storing...)

Chris..
 

Rivergator

Petty Officer 1st Class
Joined
May 7, 2013
Messages
224
Thank you Chris and as usual you are probably right. I guess it is always sloppy. Where I come from it's called sloppy engineering or fuzzy engineering. I don't see a reason why there couldn't be a proper drainage passage in the bellhousing instead of doing something sloppy like this at the expense of a properly sized lower bushing. Maybe there is another valid reason for the excessive tolerance. But to my surprise it is what it is. I requested the specs for this bushing kit from Mercury and it is close to my measurements, so I must assume it is done by design (I am rolling my eyes), but WHY? I wonder how many unsuspecting weekend mechanics have replaced this set unnecessarily thinking the bushings are worn when they are actually not. I am one of them. I mean it's not a big deal. the old bushings are already out so, of course, I will install the new set, only to have the same play in the shift shaft as before. I guess some days are better than others - LOL!
 

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