Yamaha 3.1 ox66 lower unit on a 2.6 engine?

**reacler** · 05-03-2022, 03:27 PM

As the title says, is it possible to fit an early 2000's yamaha 200hp 3.1L lower unit on a 1988 yamaha 225 excel 2.6L? My research has lead me to believe they will bolt up and run but the fit isn't pretty. This wouldn't bother me as long as it doesn't leak and there are no adverse effects besides aesthetics.

Can anyone shed some light on this?

**David** · 05-03-2022, 07:32 PM

Hydrotec would know

**reacler** · 05-04-2022, 07:35 PM

Thanks, hopefully he'll chime in and confirm. I made a few phone calls and I think I'm confident enough to pull the trigger on it.

For anyone else that may stumble on this thread in the future...

The newer 3.1L Yamaha lower units will bolt up to an older 2.6L engine and run. Casings are different shapes, probably wont mate up seamlessly to midsection. Also the 3.1L lower has a 1.75 gear ratio where the 2.6L has 1.86 or in my case 1.81 for the 225 Excel.

**bakerfreak** · 05-06-2022, 10:58 AM

Originally Posted by reacler

Thanks, hopefully he'll chime in and confirm. I made a few phone calls and I think I'm confident enough to pull the trigger on it.

For anyone else that may stumble on this thread in the future...

The newer 3.1L Yamaha lower units will bolt up to an older 2.6L engine and run. Casings are different shapes, probably wont mate up seamlessly to midsection. Also the 3.1L lower has a 1.75 gear ratio where the 2.6L has 1.86 or in my case 1.81 for the 225 Excel.

I like the idea but what is your reason? To take advantage of the higher gearing? It seems like a big effort compared to the price of a propeller.

**reacler** · 05-13-2022, 11:06 PM

Originally Posted by bakerfreak

I like the idea but what is your reason? To take advantage of the higher gearing? It seems like a big effort compared to the price of a propeller.

I have a few propellers of varying pitches so that's not really an issue. I exploded my lower last year (literally casing sheared in half) so I've been looking for a new one. Came across one on ebay that was in good condition and had a bobs nosecone lwpu already on it, factory installed by bobs. I was able to get it for under a grand shipping included so I couldn't pass it up. Saves me a ton of time and effort since now I dont have to put the nosecone on myself.