Mc-1 lower unit on a alpha one upper unit.

[Speed1v8]

Hi I have a mc-1 lower unit that I want to know if I can put that lower unit on the alpha one upper. Would appreciate some help thanks.

 

[Don S]

Re: Mc-1 lower unit on a alpha one upper unit.

Not sure if you can or not. But it will fit.

 

[Speed1v8]

Re: Mc-1 lower unit on a alpha one upper unit.

Thanks don any one else have anymore info

 

[Speed1v8]

Re: Mc-1 lower unit on a alpha one upper unit.

What about the upper gears I heard they all fit. On each other and I'm aware that theirs different gear rations. Am I correct

 

[sharkin95]

Re: Mc-1 lower unit on a alpha one upper unit.

yes you are correct on all alpha 1 up to 1990.does the lower unit have a pre load pin on the driveshaft?

 

[Speed1v8]

Re: Mc-1 lower unit on a alpha one upper unit.

The lower is mc1 and not sure about pin you taking about but I'm sure it does have it. Is that problem if it has it

 

[cpt ron jc]

Re: Mc-1 lower unit on a alpha one upper unit.

I also have a 1990 alpha 1 the lower on mine is bad,i found a good working MC1 83,i would like to change the whole outdrive or match the bottom up to my top i seen a picture with the pin from the mc1 ,,,,,,,,,,,not sure but i am about to find out soon.,no one seems to know crap shoot.......

 

[Speed1v8]

Re: Mc-1 lower unit on a alpha one upper unit.

Yea well I saw diagram and the pin is right above the impeller housing on shaft some say you don't need it some say you could use it but I saw it. Well you can put that whole outdrive
On your alpha one as well but not recommended by mercruiser. People have done it . I have a bad gear that chipped on top but that easy to fix with the tools.

 

[Eric 3.7LX Alpha 1]

Re: Mc-1 lower unit on a alpha one upper unit.

Here are pictures of a MC-1 and Alpha One side by side. Note the pin on the top shaft on the MC. You can not remove it, but the newer Alpha upper wil bolt up to the MC with that pin, no problem.

 

[cpt ron jc]

Re: Mc-1 lower unit on a alpha one upper unit.

ok great so your saying you can put the whole mc1 drive on to mine,will the main yoke match into my copuler,or shouldi just change out the bottom half ,my top is still in working order,i am going to pick up the drive later,should you be able to turn the bottom and top by hand .thanks much eric

 

[ktbarrentine]

Re: Mc-1 lower unit on a alpha one upper unit.

Yea well I saw diagram and the pin is right above the impeller housing on shaft some say you don't need it some say you could use it but I saw it. Well you can put that whole outdrive
On your alpha one as well but not recommended by mercruiser. People have done it . I have a bad gear that chipped on top but that easy to fix with the tools.

Just curious....where did you hear / read that this is not recommended by mercruiser?

 

[Speed1v8]

Re: Mc-1 lower unit on a alpha one upper unit.

It works bolts right up. On the manual but they will always say that so you can spend more money on their products. If you got it for cheap go for it. The yoke won't fit if it came out of a v8 cuz the yoke be lil longer. If it came off a 4 cylinder than your ok. Other than that you could. Oh and yeah it should spin by hand also open the top cap with 4 bolt on upper part of outdrive to check gears. Good luck

 

[cpt ron jc]

Re: Mc-1 lower unit on a alpha one upper unit.

OK thanks i will give it a shot,i will just use the bottom,why make more work than need be ,my upper works fine.

 

[Speed1v8]

Re: Mc-1 lower unit on a alpha one upper unit.

Yea try it let me know how works out.

 

[cpt ron jc]

Re: Mc-1 lower unit on a alpha one upper unit.

Ok i tried it goes on almost all the way,i can not get it all the way in,i jiggle it back and forth,still will not go all the way in,it looks like the main shaft on the lower is the same size.any ideas.

 

[Bondo]

Re: Mc-1 lower unit on a alpha one upper unit.

Ok i tried it goes on almost all the way,i can not get it all the way in,i jiggle it back and forth,still will not go all the way in,it looks like the main shaft on the lower is the same size.any ideas.

Ayuh,.... Ya gotta line up, All the pieces/ linkages/ pipes, at the same time,.... Not so much jigglin' it...

 

[cpt ron jc]

Re: Mc-1 lower unit on a alpha one upper unit.

OK all the holes line up,i am trying to turn the shaft on the lower will not move,i try to shift the lower so i can move the shaft near the impeller,will not move while turning the shift counter clock wise.

 

[Speed1v8]

Re: Mc-1 lower unit on a alpha one upper unit.

Weird should turn in gear that's your problem that shaft not moving so to get it in is hard. Should slide in then couple taps go up if it's lined up.

 

[ktbarrentine]

Re: Mc-1 lower unit on a alpha one upper unit.

Have you been able to turn the vertical drive shaft (the one that connects the upper to the lower) clockwise (with the lower unit separated from the upper)? With a new, PROPERLY LUBRICATED and BIASED impeller installed, the shaft should turn clockwise (normal direction) with some resistance, caused by the impeller friction in the water pump housing.
Another thing.. since this is an MC-1 lower.... do you have the O-ring installed on the top of the vertical shaft (below the splined area)? This O-ring has caused problems when trying to manuever it past the shaft seal in the upper housing (that shaft seal is to keep water out of the splines of the vertical shaft in the upper housing). Most people are leaving that O-ring out because the shaft seal provides that seal and the O-ring is not needed (the o-ring groove does not even exist on later versions). Others (like me) have successfully pushed that o-ring past the shaft seal, but I intend on leaving it out next time.

 

[Speed1v8]

Re: Mc-1 lower unit on a alpha one upper unit.

Yep right on that's what's probably stoping you just take it of that o ring don't need it