comp prop

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  #1  
Old 12-05-09, 02:51 PM
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comp prop

Hey guys i currently have a 3 blade prop on my evinride 135hp i was wanting a little more bite for pulling a skier the new comp prop i am looking at is a 4 blade they say it will not decease my top speed (Noticably) like 1 mph Do you guys think this is a smart move.. my other question is on my old prob it does not say what pitch it is or am i looking in the wrong spot.. will i need to stay at the same pitch if i decide to switch 3 to 4 blade comp prop Thanks for any info This is all i could find on the prop 247 k 665 x but whats the pitch Im thinking of going with a 19 pitch but would like to know what pitch the one i got now is but i think 19 would be ok tell me if im wrong
 

Last edited by tsherrill10; 12-05-09 at 04:36 PM.
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  #2  
Old 12-06-09, 06:13 PM
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  #3  
Old 12-06-09, 09:58 PM
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A 4-blade 19-inch pitch may or may not help pull a skier out of the hole.

The more important question is, how much does the boat weigh? On a properly powered boat with the correct prop, a 135 should pull a skier with two people in the boat. If your entire family and a couple of the neighbors' kids are in the boat, it may take awhile to get that boat on plane -- and get the skier out of the hole.

In that case you should go to a lower pitch for more power. A 17-inch prop will give you quite a bit more power for skiers. But you'll lose top-end speed. You'll also have to watch the tach closely at WOT because it could cause the engine to over-rev.

I know several boat owners who trailer & change the prop before they put the boat in the water. If they plan to cruise, they use a higher pitch. If they plan to ski, they use the lower.

We also are fortunate to have some nice secluded beaches where we can drop off unnecessary weight (bodies, coolers) when someone wants to ski.
 
  #4  
Old 12-07-09, 10:20 AM
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prop

Yea im clueless about how much this boat weighs i would guess 1500 to 2100 its an old browning tri hull i dont know the model of boat it is cant seem to find one just like it the only one i know that is close is a browning mustang from looking at pictures on the net is there any way to find out what pitch the prop i have now is any way to measure the pitch on it.. oh and the boats 16 ft long it light enought i can push it around by hand in the garage thanks for your reply just dont know what prop to order debating 17 or 19 pitch I would go with the 19 pitch for cruzing and 17 for water sports but i have heard that running a two stroke at a lower rpm than recommended operating range is actually worse than running at a high rpm this makes no sence to me
 

Last edited by tsherrill10; 12-07-09 at 12:19 PM.
  #5  
Old 12-08-09, 03:46 AM
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A prop with too high of a pitch will not allow the engine to achieve full RPM. It will dump too much fuel into the cylinders and eventually cause a carbon buildup and foul the spark plugs. Your WOT on that motor should be around 5,500 RPM.

Most props have the pitch stamped into the outside of the center hub.

A tri-hull won't get up out of the water as fast as a V-hull, and they are usually quite a bit heavier then the same size V-hull.
 
  #6  
Old 12-08-09, 09:58 AM
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okay thanks rick for your help in this case i think i will start with a 17 and if its too low i go 19 i have on it now is so old proply the original and this thing weighs 20 pounds i read the one i am looking at weighs 4 pounds heck that alone should help
 
  #7  
Old 12-09-09, 07:42 PM
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Rick is right on. I use a different prop depending on what I plan on doing and how many people I have in the boat. I have gotten good at changing props out from leaning out from a buddies boat.

If your thinking about a composit prop they aren't the best for skiing. They will flex too much from what I understand. The water cops use them arround here so when they hit rocks it doesn't bend the propshaft.
 
  #8  
Old 12-09-09, 07:57 PM
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okay thanks a lot for your help guys im short on cash that is why i was going for the com prop there really cheap prolly because of what you said about them flexing.After feeling how heavy the prop that is on it now was why i am really thinking about getting a new one or does the weight not matter.. i was thinking lighter prop would be better or am i wrong on this.. i think i will save up and get me a aluminum prop instead of the com thanks guys todd
 
  #9  
Old 12-12-09, 04:10 AM
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I doubt there would be a noticeable difference in performance between a heavy prop and a lighter one. Stainless steel is quite a bit heavier than aluminum, yet stainless is recommended over aluminum for high-performance rigs.

The change that will affect your boat's performance the most is changing the pitch.

Either way, don't dismiss the idea of buying a used, refurbished prop from a local repair shop. They are generally cheaper than new with the added benefit of being balanced by a human hand rather than a machine.
 
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