another prop size Question

[dude33333]

sorry! <br />i just wrecked my prop in an unusual way, by my boat flying off the trailer while towing. anyways, its time for a new one..... i have a 17 ft. tri-hull w/a 50hp. johnson that will be used mostly for puttin around maybe a little water skiing and fishin. i have no clue how heavy the boat is, 800-1200 lbs.? and i got all the numbers i could off the motor: model:50esl75b #: e4264596 its got a shaft with 13 grooves in it and i tried to measure the prop, looks like: 5.5 inch radius 3 inch long fin and slants a total of about 3 inches across per fin... oi i know most of that was uneeded

 

[roscoe]

Re: another prop size Question

Try to find a part number or the diameter and pitch numbers off the prop. You may have to remove the prop and look "inside".<br /><br />Did the old prop perform acceptably?<br />Were you hitting 5500+ rpm at full throttle before the mishap?<br /><br />If so, replace it with the same sized prop.

 

[LubeDude]

Re: another prop size Question

Sorry to hear about your misshap, I know that its sometimes hard to wait, but next time wait untill you get to the water before you launch.

 

[dude33333]

Re: another prop size Question

ok it says 11 3/4 X 17 sound right? im not sure wether it was good or not, i was having some engine problems. im looking around at props online and im not sure which ones fit my particular make/model.. should all the 13 groove shaft ones fit? or are some different?<br />thanx<br />~erk

 

[dude33333]

Re: another prop size Question

also, what do people think about the composite pirhana props?

 

[Jack Shellac]

Re: another prop size Question

A 50 HP is pretty small for that size boat. I'm sure you need to go down in pitch to get your RPM's in the upper quarter of the WOT range where you need to be. Without a tachometer, you're just guessing as to whether you're there or not. BUT, again just guessing, I think you'll probably wind up with about a 13" pitch to get it right. Try to find a shop that will let you try out props. I understand that the composite props do an acceptable job, but don't have any first hand experience with them

 

[ob15]

Re: another prop size Question

You definitely will need lower pitch. I have a 15' vee hull boat with an older 50hp & get 5700 rpm out of mine with an 11 3/4 x 17 prop.

 

[dude33333]

Re: another prop size Question

ok so 13" pitch? i guess that means a 12 2/4" x 15" is to big? becuase theres one on ebay for pretty cheap. anyone else have suggestions?