converting a 1999 115 yamaha 20" shaft to a 25" shaft

Good Afternoon,

I have a 20 foot welded aluminum workboat with a 115 yamaha 2 stroke. 20 inch. Model number 115 TLRX I need to convert to a long shaft as the waves come in over the back. I have purchased aluminum lift bracket to raise the motor up and we will add aluminum plate to it to block waves.

I also have a 130 hp yamaha 25 inch shaft. Model number 130 TXRY

My questions are.

1. Should I swap the lower sections of the motors around making the 115 a 25" shaft or should I switch the complete motor to a 130 hp which is now a 25" shaft.?

I dont need the extra power and done want to burn more fuel. Is it possible to switch the 115 hp carbs to the 130 ? Is the gear ratio the same?

All thoughts and advice are welcome.


I have owned the 115 for years and has been a very good motor. I bought the 130 from a local who said they had always maintained at the dealer and it ran well. They just wanted to go to a 4 stroke.

Any thoughts on the best route to go?

bigdockbuilder said:

1. Should I swap the lower sections of the motors around making the 115 a 25" shaft or should I switch the complete motor to a 130 hp which is now a 25" shaft.?

Click to expand...

The 115hp & 130hp are practically mechanically identical...the 130hp has a little bit higher max fuel consumption and compression pressure, and it weighs about 20lbs more, but that's about it. So to me it seems foolish going through the cost and effort of exchanging LU's. If the 130hp is reliable and has been well maintained, I'd hang it.

There may be as engineered kit available to add 5" to the motor.

I thinkyou are right.

Going with the 130 is probally alot less work.

Thanks for the insight.