Prop upgrade question

[Baitcaster]

I have a 40 hp VRO Johnson with a 12 1/2 X 13 prop. I have no problems getting out of the hole. The motor is reaching max rpms and the boat speed is only about 21 mph. Could changing the pitch of the prop give me more speed at the same rpm? Any suggestions on what pitch I should get. Thanks

 

[Perfidiajoe]

Re: Prop upgrade question

The only problem is w/ a larger pitch prop, will the engine get to the same RPM. I would bet not! It might help if you are turning too many RPM's good Luck, Joe

 

[Dhadley]

Re: Prop upgrade question

Whats your top rpm with an average load?

 

[steelespike]

Re: Prop upgrade question

Im not an expert but::<br />We could do a better job if you give us the year<br />and max rpm for the motor and what boat(fiberglass,aluminum, style?) it is on.<br />Is the motor in good tune with good compression?<br /> A good sound motor may handle an increase in pitch.They say an inch change results in about 150 to 200 rpm change.It is possible at max rpm you could go with a cupped prop, drop a little pitch and you might keep the same rpm but might gain a little speed.Someone should be along with better knowledge.

 

[Mark42]

Re: Prop upgrade question

Baitcaster,<br /><br />My little 14.5' boat is running a 40hp with 12.25 x 15* Hustler aluminum prop. Boat speed varies. With wife and 3 kids, 12 gal gas does 28 mph. With just me and 12 gal gas does 30 mph, 5000 rpm. Best performance is with trim pin set fully trimmed in. Jumps right up on plane.