boat will not plane out

[gregscharf]

I have a 1972 Chaparrel 15' with a 1964 Johnson 75 HP outboard and the boat does not plane out unless it's at full throttle. I have been told I need a whale tale or a different prop. I checked into the prop and it matches the engine. I am new to boats and need some advice.

 

[walleyehed]

Re: boat will not plane out

To plane out, you should use full throttle, then back-off once on plane...<br />How do you know prop matches engine???<br />What we need to know is what is your wide open throttle RPM-that tells us if the prop is matched up.

 

[LubeDude]

Re: boat will not plane out

Welcome to Iboats.<br /><br />A 15' boat of any kind with a "Propper" running 75 HP engine should have "0" problems getting on plane with the right prop and should run 40-45 MPH, maybe a bit more depending on the hull<br /><br />Now, are we sure the engine is running propperly and we have the right prop? The prop matching the engine means nothing, the prop must match the setup, (Boat engine combination).<br /><br />We need to know the current pitch of your prop, you RPM at WOT and the relation of your cavitation plate to the bottom of your hull. (X dimention). Then we will be able to give some advice.

 

[gregscharf]

Re: boat will not plane out

I don't have a tach on the boat, so I don't know the rpm's at full throttle. I will have to get back to you tomorrow about the props that I have and where the cavitation plate is. I checked out the props with a prop shop and they pulled out their books and it showed that the two props I have are for that engine for that year. I will have the other information tomorrow. Thanks.

 

[walleyehed]

Re: boat will not plane out

several props are available for that engine, but the correct prop for YOUR application can ONLY be determined by tachometer. The Tach will tell you more than any other instrument you can have as to how the boat is performing with "X" prop.

 

[LubeDude]

Re: boat will not plane out

Walleyehead is correct, "NO TACH, VERY LITTLE HELP".

 

[JB]

Re: boat will not plane out

Duplicate. See Boats.