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chillincarp870

Pitch on props?????

13 posts in this topic

Pitch is somewhat like putting different sized tires on a car. Too big and the motor can't turn the rear wheels. Too small and you'll over rev the engine but not go very fast.

Imagine putting monster truck tires on a Geo Metro. It has a small engine and won't be able to get those big tires moving real well and the engine will bog down. Now put training wheels on that Metro and you'll spin them all the way down the street but when you get on the highway the motor will be rev'd way up and you can't go very fast because the engine is at the limiter.

There is a window where the right pitch works best with the boat style, weight, and engine. Most of the time it's preferable to select the pitch so that max engine RPM is near the top of the manufacturer's recommended limits.

Prop pitch is only part of the puzzle as you can get into multiple blades and different blade styles, but after you find the right pitch you then can play with the other variables if you want to really squeeze the last bit of performance out of your boat.

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is it really that big of a deal for a duck boat on what pitch to get? or would you go somewhere in the middle of the pitch available as i don't know the rpms of the motor

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I wouldn't think so as long as it isn't too small so your over revving the engine.

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On a duck boat with a small motor, just use the prop that came with the motor. Changing the pitch on the prop will not have any useable effect. If you are looking to improve your performance, you may want to investigate what is available in weed resistant propellor designs.

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i am not sure what pitch it was and i need a new prop. it is a 2001 25hp merc. what would you guys reccomend

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If you are just looking for a general purpose prop, try to find a 3 blade aluminum, 10 X 11" or 12" pitch. I would not go any higher than that in pitch, and the diameter will be a standard for the gearcase on your motor. Look for a good deal and try not to spend too much. Soderblooms is probably a good bet for you.

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Do you have your old Prop?

If so, take a look at it - it should be stamped in the hub area on the outside - you're looking for a number with the letter "P" before it. As hydro said, it'll probably be a 11 or 12

If you don't have your old prop, or you can't find the pitch of it, I'd give Jay Soderbloom a call; he should be able to point you in the right direction.

marine_man

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Marine Man I was wondering if you would have any idea on proping a fish boat boat for more speed by knowing what the boat size and motor are. Or any other fmrs know about proping a fish boat. Its a 1994 Lund Angler Deluxe with a 1992 40hp johnson. Right know with me (230 lbs) and any passanger I can go about 23mph gps speed. Is that about right or is there more speed to be had. I dont have a tach so I guess I dont need my max rpms. I guess I am wondering more or less if that speed is what others with similar package are getting

--I will run out to shed and check my prop size and update

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That sounds pretty close to what I'd expect.. what is your holeshot like?

The prop size would help as well... or are you still out in the shed grin

marine_man

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Prop size is 12.5x13. boat has good holeshot and plains out fine

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I would say that's pretty close to the right prop.. you could maybe try a 15, but I'd want a tach to verify it before I changed.

marine_man

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