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My 17' Whaler will not plane with its 65 hp Mercury. Any advice?

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Perhaps you could share a little more information. What year and model of 17 footer is it? Did it used to plane, but now will not? Or is the boat new to you and it does not plane? What propeller is on there now? Model? Pitch and Diameter? Material? Age? When was the motor last serviced? Is the boat kept in the water? If so, how clean is the bottom? How much does the hull weigh?

I can think of several reasons why a boat like a 17 foot Whaler with 65 HP will not plane even though 65 HP is more than enough under normal circumstances. With a little more input from you I am sure we can solve this puzzle.

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Thanks for the reply. It is a 1964 model. I dont know how it was befor I just got it and had the 65 hp put on it as it did not have a motor when I got it. The propeller is a 3 blade 13 inch 19 pitch aluminum. It is made by solas. It is brand new. The motor was just serviced 3 weeks ago. The boat is not kept in the water. It is clean. Idont know the weight of the hull. Thanks so much for the help!

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Quick guess. Your pitch is too high for the engine. I am using a 90hp on my 16' 7" 1969 whaler, it is 13" 19 pitch aluminum and works pretty well. If your pitch is too high for the engine/load you will be unable to reach max rpms, if too low you could over rev.

just a thought, good luck,

dana

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duc,

Suggestion... don't buy any props... Try and borrow them if possible until you find the correct match for your boat.

My 1978 Montauk with a 1985 Evinrude 70hp used a 13 3/4 x 15 pitch prop...
I could also use a 13 1/4 x 17 pitch prop but it was slower out of the hole...
These were all standard OMC Aluminum props...

I think a 19 pitch prop is way too much for a 65hp engine.
You don't mention what year the engine is?

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I'm not sure what year the motor is. How can I tell?Thank you.

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duc,

I am not a Merc man but you should have two identifying sources on your engine.
1. Serial Number
and
2. Model Number
One or the other, or both, we tell the secrets.... Post your numbers here and someone will be able to tell you the year and probably a little more info too....

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Ah. I think we have found the problem. A 13" x 19" Solas is WAY too much prop for that old motor. Mercury has not made a 65 HP model in many years and I suspect yours is a 1960s or 1970s model and will thus perform more like a 50 HP or 60 HP model from today.

You should try to experiment with a 15" pitch propeller to start. A Mercury Vengeance would be a good starting point.

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I found out that the motor is a 1967.

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I had the same problem, I had a 115hp on a 17ft, the boat was a 1969. I did a thourough inspection to find it was water logged.

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I ran a Merc 50 4 stk on my 99 Montauk and found that a 13 pitch was the ideal prop.

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When you say it won't plane....is it plowing or porpoising?
You're aware there are 4 or 5 motor trim adjustments available via that big pin just under the front of the powerhead? Each setting will make a drastic difference on how the boat will ride....
I grew up on and still have, your boats' older sister...ran a Merc 650 with NO problems for 20 years.... that boat should scoot along with any of the props mentioned....a DoelFin wouldn't hurt either....
What's the scoop with that motor trim position?
Dan