Is there anything that can be done to a Yamaha Pro 50

[mattmak]

Hello,
I'm wonderig if there is anything that can be done to a Yamaha Pro 50 (1993) to get some more horsepower out of it.
My current setup consists of a 13.5 foot fiberglass runabout (pretty light boat) that does about 40 MPH with the stock 14" pitch Stainless Steel Prop. The boat is heavier than the 13 foot hydrostream VooDoo, and not as "hydrodynamic". with just me in the boat, It revs to the proper RPM (5700), but under load it lacks the punch that it has when there is only me in the boat (5400 RPM). I'd like to either get more accelleration out of it, or get enough horsepower to move to a bigger prop (to have a bit more speed in the top end). Either result would be good, because after purchasing the bigger prop, I'd have both props and could choose which one to use depending on what I want out of the boat.

I really enjoyed the power the engine had when I was a teenager, but now that me and my friends have put on a few pounds, we could use more horsepower.

any advise would be great.

Thanks, Matt

[Markus]

You can have your head cut to get more compression or buy Hydrotec's Yamaha 50 head. That will give you more torque across the RPM range.

Hydrotec also sells a tuner for that engine, but what you gain at the top, you will probably lose at the bottom.

Since Hydrotec sells parts for the small Yamaha engines, maybe they know how to port them as well. It does not hurt to give them a call, but it will probably not be cheap compared to a 70 hp engine of the same age.

[Rybino]

Hey Matt,
If you decide to let the motor go, and purchase another with more horsepower. Let me know! I love the yamaha's!

Just for kicks where abouts are you located?

[mattmak]

Are you really in Milton? that's convinient... I'm in Guelph.

My ultimate goal/project would be to rebuild the transom of the boat, sell the Pro 50 and get a 70.

I wasn't sure if I should do that this summer/fall or wait 1 year, but your interest in the Pro 50 has sparked my interest in working on the transon.

I'll start looking around for a 70.

Matt