Mercruiser lower units swap alpha I---- 4 cyl - VS - 8cyl

[calamari]

Can anyone tell me will a lower unit of a Mercruiser alpha1 outdrive from a 4 cylinder engine work on a Mercruiser alpha 1 (1986) outdrive with a 8 cylinder engine.

I broke the skeg completly of my lower unit at the bullet so I have to buy a skeg and weld it on. But my brother has a old alpha 1 lower unit from his boat which was a 4 cylinder engine. If his old lower unit will work on my boat powered by a 8 cylinder that would be the best way for me to go that is if it will work

 

[Bondo]

Re: Mercruiser lower units swap alpha I---- 4 cyl - VS - 8cyl

Ayuh,... The Lower units are generally the Same...

 

[steelespike]

Re: Mercruiser lower units swap alpha I---- 4 cyl - VS - 8cyl

My sister wrecked her 120 hp gearcase on a shoal and they put a bigger V8?outdrive on temporarily don't know if they changed props.At anyrate
the 120 could barely plane with it.

 

[hwsiii]

Re: Mercruiser lower units swap alpha I---- 4 cyl - VS - 8cyl

Squid, it would be better to fix yours. The gear ratio on the 4 cylinder is probably 1.98:1 and V8 is probably about 1.32:1 and I don't know the other differences.

H

 

[Bondo]

Re: Mercruiser lower units swap alpha I---- 4 cyl - VS - 8cyl

Ayuh,... Hwsiii, 'n Steelspike,... The gear ratio is determinded by the Upper unit...

All the alpha series(1s, Rs, MRs, etc.) of drives up to, but Not including the Gen.IIs are 1.65:1 in the Lower units...

 

[hwsiii]

Re: Mercruiser lower units swap alpha I---- 4 cyl - VS - 8cyl

I didn't know that, thank you Bondo.

H