Prop for 35 evinrude?

My buddies boat is a 1979 16 foot monark aluminum bass boat. Identical to the bass trackers. It has a mid 80's evinrude 35hp on it with a 11 pitch prop. He doesn't care about low end torque. He fishes with about 1-4 people. With the current prop it tops out at 27mph. He's wanting more top speed. Can't get rpms for ya. No tach.

Re: Prop for 35 evinrude?

Anybody?

Re: Prop for 35 evinrude?

Without the rpm you can't really make a reccomendation.
A tinytach is reasonable and easy to install.Can used on other 2 cylinder 2 strokes. We need the rpm just to try to tell which way to go from your present prop.For the health of the motor it must operate within its rpm range. 5,800 is the max rpm you should prop close to that number.
The tach will also tell whether you have selected the right prop.
Is the speed by gps(best) what kind of load, batteries, gas,live well? people.
Dry weight of the boat?

Re: Prop for 35 evinrude?

The boat is rated for a 65hp. It's gps speed wot is 27.4 flat water 2 people 2 batteries very little gear. Gas 6 gallons. Empty live well. Boat weight unknown. The motor needs a higher pitch prop for sure. I'm thinking 15-16P?

Re: Prop for 35 evinrude?

If you get us the model number we can tell the year of the motor.
Under 1985 motors the 11" is about in the middle with 3 below and 4 above stopping at 15.
Boat is rated at 65 hp typically it is suggested to have 2/3 to 3/4 of the rated hp.
Your barely over 1/2 the rated power.If it ends up over propped you will have poor hole shot
difficulty staying on plane at reduced throttle,poor mileage and premature engine problems.
Thye motor is rated at 5200 to 5800 rpm.
The difference in rpm with one inch pitch change will likely be more than 400 rpm.I think you can see
if your presently at 5500 you could easily drop below the the 5200 rpm rating.You could gain some speed
But likely on the edge of the bottom rating and will drop out with 4 aboad even if it will plane with 4.
Another way to gain some speed at no cost is to raise the motor.If it has a through hub exhaust you may be able to raise it so the antivent plate is about an inch above the bottom.Could gain a couple of mph.