whats my next move?

[bigbass55]

hello again. ive been trying to get my boat setup right but have run into sum issues.i have a 92' 40 hp 'rude on a 17 ft tracker aluminum bass boat with a cmc power t/t and stingray hydrofoil. with my old 11 3/4 x 17 prop i could turn 4900 rpm. i got a new 12 x 15 vortex prop and can get maybe 5000-5100 rpm at wot. i tried raising the engine 2 holes as it was in the lowest posistion possible but it ventilated a lot and i didnt like that much. so i lowered back down 1 hole and get my 5000-5100 rpm. i dont kno what to do now. i realize i need to turn at least 5500 rpm. any help will be appreciated

 

[Dhadley]

Re: whats my next move?

Doesn't sound like the Vortex has much cup if it vents that easy. Have you tried any other props?

 

[bigbass55]

Re: whats my next move?

well it said it was cupped. i mean it would vent a little on holeshot and i couldnt trim very much. maybe a little over half of what i usually can trim. it vented in turns pretty good also. the rpms went up to around 5300 when it was higher. should i invest in a good ss prop?

 

[walleyehed]

Re: whats my next move?

The Vortex's I've run, DH, look to be best suited to sterndrives more than outboards...<br />I know they say they have apps for outboards, and that's what I've run but cup is not very obvious and they don't have much for cross-section...pretty flat.<br />Bigbass55, if ya got the bucks, look into SS, no doubt.

 

[bigbass55]

Re: whats my next move?

what ss prop would u reccamend?

 

[walleyehed]

Re: whats my next move?

Several SS props are available for your engine, and I learned the hard way on these smaller ones, it seems to be best if you can keep the diameter as big as possible. I recommended a Turbo Hot-shot for a 50HP on about the same type rig and it wanted to vent a bit more than he liked. That guy went to a Ballistic and likes it....not "my" first choice, but it worked out for him...<br />Let's see what Dhadley has to say...he's better at this than I am, and usually more accurate on the first try...

 

[Dhadley]

Re: whats my next move?

I agree on keeping the diameter as big as possible. I have a 11 3/4" Turbo we could try but its a 17" pitch. That's not going to do us any good since you already have that.

 

[bigbass55]

Re: whats my next move?

would something like a 12 x 13 ss put me in the right rpm range?

 

[Dhadley]

Re: whats my next move?

That would seem to be where we need to be. What brand prop is it?

 

[Texasmark]

Re: whats my next move?

I personally don't worry about venting in turns, especially when you are talking about a couple hundred rpm's. Should lock back in as soon as you straighten out. Mine does it all the time and it's like running a vented prop and when the vent closes the rpms drop and it sounds like you are in overdrive in a car.<br /><br />Now if you were blowing completely out and rpm's went to the wall and the boat stalled,then I'd be concerned about that.<br /><br />If you are swapping props check out the prop deals advertised herein. I just saved a ton of money on exactly the prop I was wanting to buy but couldn't see spending the retail price for it.<br /><br />My 2c <br /><br />Mark

 

[bigbass55]

Re: whats my next move?

i dont have a water pressure gauge and i dont wanna harm the engine. so im assuming that sum venting wont burn my motor up oh i forgot to post that my top speed is around 28 with 2 men light load, 27 2 men larger load, 26 2 men with livewell full

 

[bigbass55]

Re: whats my next move?

bump

 

[walleyehed]

Re: whats my next move?

OK, I wasn't going to throw this in, but I have a 17ft Tracker 10yrs older than yours with a 40HP...the hull is a bit different, but an 11P is as much as I could spin the correct RPM, but I'm also at 3600ft above sea-level...I installed a 70HP 3-cyl Merc and found a 13P was best suited to my load and 5800RPM. To be in the right range, I think you're going to be in the 12-13P range with the 40 at sea-level (or close) on that boat. My boat vents when I turn and even when I blast off sometimes, and it's not because the engine is too high, it's just a poorly designed hull. Make sure you have nothing mounted on the transom, like a transducer, within 12" of center, either side.

 

[bigbass55]

Re: whats my next move?

how do you guys feel about a 11 3/4 x 13 rapture ss cupped prop for my application. i was looking here on iboats and it is $154.29, sounds reasonable to me. thanks in advance also would this prop allow me to raise the engine 1 hole?

 

[walleyehed]

Re: whats my next move?

I think it would be a good place to start for the price. The Rapture is a pretty good all-around prop.

 

[bigbass55]

Re: whats my next move?

what do you guys think that prop would do to my topend speed?

 

[bigbass55]

Re: whats my next move?

bump

 

[MurdockJr1]

Re: whats my next move?

Bigbass you are ignoring your other post (can't get rpm up) I already told you what you need to do. Why don't you try an 11 X 11 pitch or a 10 X 12 Pitch and see what that does for you. You need to get the rpm up on that engine or it will die. You may be surprised what that will do to your top end and hole shot.