prop question for 2002 90hp Yamaha

[Plugneck]

My boat is a 20' (2072) Crestliner modified-v jon boat with a 2002 90hp Yamaha. The oem prop on it is a 13 1/4 x 17 and runs pretty good with it. The original prop is getting chewed up so I replaced it with a 17 pitch Comprop. The boat runs very sluggish with this prop. Figuring this is because of the 4 blade design I purchased a 13 1/4 x 17 Quicksilver prop with a Flowtorque II hub kit. Same thing, slow holeshot and topend. Is this normal that two identically pitched props of different brands to perform so different? Why would this happen? My boat currently does not have a tach and I plan to install one before I get too wrapped up in this. Tonight I ordered a Rapture 13 1/4 x 15 prop, mainly because it was on sale for less than half the normal price. I know without a tach I won't know for sure but does this sound about right for my setup? Any suggestions? Thanks.

 

[Dhadley]

Re: prop question for 2002 90hp Yamaha

A couple of things -- without a tach youre shooting in the dark. As you've discovered just throwing money at it doesnt solve the problem.<br /><br />It's really hard, if not impossible, to compare two props of the "same" pitch in different brands because todays props have so much progressive pitch, cup and rake. <br /><br />Next, you're comparing 3 and 4 blade props without adjusting the X dimension. And you're comparing aluminum (we assume) to plastic. Not to mention different styles.<br /><br />We have to establish a baseline. Without a tach you can't do that. The end result will most likely be a lot of $$$ spent and a hurt motor.<br /><br />For the money you've spent I'd bet you could have bought a couple of tachs. Oh -- don't skimp on the tach. Get a Yamaha tach thats made for that motor.

 

[Ron G]

Re: prop question for 2002 90hp Yamaha

You defently need a tac how do you know exactly what your motors doing?you may have to work with your setup on each prop first instead of swapping around,its always best to start with one for your baseline and tweak it untill its at its max performce then go to another prop,JMO<br />D you sure are typing fast this morning.

 

[Major Woods]

Re: prop question for 2002 90hp Yamaha

I have a G3 2072 john with a 90hp Yamaha.<br />I use the Yamaha 13 1/4" x 17 aluminum prop, that is the correct one for the boat.

 

[Plugneck]

Re: prop question for 2002 90hp Yamaha

I just ordered a Yamaha Multi-function guage with the rigging kit. What kind of things can be "tweaked" to improve performance?

 

[Dhadley]

Re: prop question for 2002 90hp Yamaha

Set up tweaks include X dimension (motor height), setback, load distribution, hull condition etc. Motor tweaks are different.