Need Prop Help

[mLuMaN83]

So I have just recently acquired my new boat. It's a 1980 Boston Whaler 11 sport. Center console, 6 gal fuel tank, and I usually have two people on the boat as well as a cooler for fish. Ive got a 25hp 4 stroke Tohatsu outboard on it and the prop needs replacing. I checked around locally and Gainesville's main marine shop does not carry parts for Tohatsu so I am kind of stuck with ordering online.

I would like to get a few more miles an hour top speed on her. I could care less about getting out of the hole fast. She planes good, but I wish it had a bit more top speed for running from spot to spot. With this motor, what should I be looking for as far as pitch for this motor and set up? Motor suggests 5k-6k rpm.

Thanks in advance.

[reelhandy]

The right prop for your set up is the one that spins at the recommended top rpm at wide open throttle, while the boat is carrying it's normal load. If your motor is spinning the prop at top rpm before it reaches WOT, or it doesn't reach top RPM at WOT, it's harder on your motor than having the prop matched to the load. Lower pitch = higher rpms, higher pitch = lower rpms. If you don't have a tach on your boat you are going to need a portable tach to hook to the engine, and start from there. You don't want to gain a few mph at the sake of running above the recommended rpms.

[fishinfool]

What reelhandy said. You need to know what the rpms are with your current prop. On average an increase of 1 inch pitch will decrease rpm by 200. For optimum performance you do not want your rpm to go below the specification range. The engine will have to work too hard and cannot overcome any changes in load, such as waves, wind, turning, etc...without the boat coming off plane.

[JIm Smith]

agree with everybody, ck with ltd motors in highsprings ,not a dealer but good people to know

[dombern34]

what you can do is call power tech props, let them know the model of your boat and motor and they will tell you exactly what you need. you don't have to buy one of their props but you can at least take the pitch they suggest will be best and go find the prop you want. they information you're gonna need is top speed, RPM's at WOT...if you don't have that information they can still get around it, it's just faster with that information. good luck.