mercury lower unit

[ebizsearch]

I just got a 1997 225 HP, 3 litle 25" shaft mercury outbaord motor with out a lower unit.
Engine only has 170 Hours running time and look new.
I have trouble finding a lower unit for 3 litre 225 hP & 250 HP O/B. & pricey.
I have found lots of 150 & 200 HP 2.4 & 2.5 litre lower units.
Will these units fit and bolt onto my 3 litre engine? Some seller say yes other No.
The spec. on gear ratio on 150 & 200 Hp is 1.87:1 and the 225 & 250 HP is 1.75:1. With only a 0.12 differance a correcting prop pitch could ofset this.
Anyone know the answer? I would save munch money, time and trouble if unit were interchangeable. Thanks for any help

 

[BAYLINER185]

Re: mercury lower unit

I think the lower units are interchangable ( alpha sterndrives and merc ourboards )but the biggest concer I think would be gear ratio. It seems to me the lower unit on an Alpha drive was the same as my lower unit on my old 115 merc outboard. The water pump housings and impellars if I remember right were the exact same parts and the physical lower units seemd to the the same to.

I think you need a gear ratio that works with your amout of HP. I think the 1.87:1 will work. I have that lower unit on my 4.3 190 HP ( mercruser sterndrive )and I think it can handle up to 225 HP. Im not 100% on that though.

 

[rndn]

Re: mercury lower unit

I don't think he is talking about swapping with a stern drive lower unit, but a different HP outboard lower unit. Correct?

 

[rndn]

Re: mercury lower unit

Welcome to the forum. I'm sure one of the experts will chime in with an answer to your question.

 

[Bondo]

Re: mercury lower unit

Welcome to the forum. I'm sure one of the experts will chime in with an answer to your question.

Ayuh,........

It would Help if you posted your Question in the Mercury Outboard forum as well........
This is the Prop forum..........