08 Nitro 750 SS prop high rpms

[brian fiebig]

Just bought a 08 Nitro 750 with Mercury 90hp 2 stroke. Stock prop for boat is aluminum 12 3/4" x 21p prop. Had a bent blade when purchase so I never knew the WOT rpm for the OEM prop. Just bought a new Stiletto SS 13 1/4" 21p prop and rpms would easily blow past 6000 if i were to let it. Do I really have to move up to a 24-25p prop for a little 90 horse outboard? Or could it be a tach problem? I was going approx 43-44mph gps at 6000rpm then backed off throttle. Thanks for the help.

 

[Berry Lindley]

I'm running a 21P LaserII on mine, is just right at 6000 WOT (# 48-899006), mine is a 750 dual console.

 

[brian fiebig]

Alright I guess it is normal. I'm guessing 6000 WOT is to high and I should go to maybe a 23P prop? Will I still be able to plane off with a 23P? Thanks

 

[TOMMY RICH]

If it's not an Opti...that's too high.

I'm running a 13X21P SS Quicksilver and getting 5400 RPM @ WOT.

Something doesn't sound right........

 

[Berry Lindley]

All I am so sorry, mine is maxing at 5500 NOT 6000 with that prop. Max rpm's on this engine is 5500.

 

[TOMMY RICH]

You're good then

 

[brian fiebig]

I'm still having my issue, 6000rpms with more throttle still left in it. New 13.25x21P stiletto 3 blade prop on my 2008 nx 750 w/ 90hp 2-stroke (non opti) Should I trust the tach and order up a new 13.25x23P Stiletto prop? Or maybe a 24P. I can't see why rpms would be so high as the stock prop is only a 12.75x21P aluminum. Thanks again for the help

 

[Berry Lindley]

I think your best bet is to get with a shop that will let you test the props before you buy one, that can get expensive in a hurry. I went by the Bass Pro service center in Hendersonville TN and got them to look up the prop numbers that my rig called for, that got me around having to go thru the trial and error process that you are doing. I did have to tinker around with the plugs to get the hole shot better.

 

[brian fiebig]

I don't think I really have any shops like that around here. They all say if you put it on you bought it. So I really am down to just ordering props until I get the right one it seems.

 

[Kirby Wilson]

A 21 pitch prop may be off. Props pitch is not all ways accurate. A prop shop can check the pitch for you. I have run 3 props same pitch and same brand and they all preformed differently on the same day.