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I AM LOOKING FOR SOME INFO ON A PROP SIZE.
I HAVE A 28 T.JASON WITH A 200HP YANMAR
THE SHAFT IS 1 1/2" THE GEAR IS A ZF/ZFE63A.
I THINK THE PROP ON THE BOAT NOW IS A 22X22 4 BLADE
THE BOAT IS USED AND I WANT TO GET THE MOST OUT OF IT.
SHE WILL CRUISE 15KTS AT 2800.
 

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Teazer
Welcome aboard.First you need to know Yanmar's specs for Max rpm's at wide open throttle for that engine.This info should easily be available online on Yanmars website.Next you need to run the boat with the existing props @ wot and see how close you come to the mfgrs specs.If you fall short of specs @ wot you need less pitch or diam. if youre rpm's are much above the specs for wot you need to increase pitch and/or diam of props.If you are within the range of Yanmars specs with the existing props then they are correct for that engine in that boat with that gear.Hope this helps some.
 

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Teaser,

Wheeling your boat when used is pretty basic. For a used boat I would do the following:

1. You should photo tach the vessel first. This means that a photocell tach makes sure that you boat tach in 100% on the money.

2. Next you must fully load the boat and sea test the vessel. Your boat with the current power MUST rev 3400 RPMs @ WOT. That is 100 RPMs over the 3300 max. We do this so during the summer when things get hot and you get a little bottom growth you may lose the 100 & still be within spec.

3. If the RPMs are short change all fuel filters first. 30 Micron for the secondary and 10 micron for the engine primary is required.

4. If you do not get all of your RPMs or too many RPMs. A couple of things must be looked at; Any mechanical problem that may hold back RPMs
Too much propeller.
Too many RPMs too little propeller.

5. Once all this is done you are know ready to figure where you are going with you propeller.

A 22 X 22 sounds like a lot of propeller for you boat. Is the 63a a 2:5 to 1. It is very important to know the ratio.

If you are in the ball park with your motor and a 2:0 gear every 1? of pitch or diameter will change RPMs by about 100 RPMs and a 2.5 about 75 RPms
Playing with wheels is big $$$$$$$$$$$

Do the above tests before bending wheels. If your spin the 22 X 22 all the way you most likely have the best wheel for your boat. In closing Go max diameter and pitch for load. You want the largest diameter on N/E keeled boats because the larger blades get to the clear water away from the keel.
 
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