mercruiser lower unit install

Ron R Cox

Cadet
Joined
Jul 26, 2022
Messages
14
After installing new impeller on my Mercruiser Alpha 1 Gen 1 I am having a real problem getting it back on the lower unit. I can get it to about an inch of coming together and then it stops.
 

1960 Starflite

Petty Officer 1st Class
Joined
Jun 23, 2011
Messages
377
Spline isn't lined up with upper half. Try turning prop while holding pressure on lower unit. You DO have both the Helm and lower in forward gear, right?
 

mr 88

Commander
Joined
Nov 3, 2010
Messages
2,179
Or your shift channel on the upper housing is not lining up with the male shifter on the outdrive itself . They should both be pointing straight ahead .
Pretty sure if your splines are not lined up ,the unit won't go in period , not get within a half inch and just stop , doesn't make sense .
 

Ron R Cox

Cadet
Joined
Jul 26, 2022
Messages
14
Spline isn't lined up with upper half. Try turning prop while holding pressure on lower unit. You DO have both the Helm and lower in forward gear, right?
Thanks, for getting back to me. Yes the helm and lower is in forward gear. It just seems like there is something stopping it from going all the way up.
 

Ron R Cox

Cadet
Joined
Jul 26, 2022
Messages
14
Or your shift channel on the upper housing is not lining up with the male shifter on the outdrive itself . They should both be pointing straight ahead .
Pretty sure if your splines are not lined up ,the unit won't go in period , not get within a half inch and just stop , doesn't make sense .
The intermediate shaft( the brass one) is new and I had to use a hammer to get it to go all the way down on the lower unit spline. I pulled it off and put it back on the lower unit. It is going on but I think it may not be going down all the way. It does go down far enough to shift but will not shift into neutral. Very confusing.
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,362
Check the upper drive shaft area for a buggered seal. Also the early gen 1s had an o ring on the shaft that could get caught up there.
 
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