Prop pitch questions

[Robert Jenkins]

I have a 2005 tracker 185pt with a mercury 2 stroke 90 it has a problem coming out the whole it won't even stand up it has a stainless prop not sure what the pitch is I'm wondering what would be the best pitch prop for this boat and how fast do you think I could get it to go it just seems very weak my mechanic checked the compression said everything was good as far as the motor end any help would be greatly appreciated thanks

 

[Sean Troy]

Need to know your rpm's at WOT. Look on the prop for the pitch. Need that info also.

 

[Robert Jenkins 2]

I'm getting between 5100-5200 at WOT not sure on the pitch because I'm at work offshore and I don't no but I'm trying to find out thanks

 

[Sean Troy]

5000-5750 RPM is the optimum at WOT. Sounds like you could drop two pitches to get on target. It is a three blade prop you have?

 

[Robert Jenkins 2]

Yes it's a 3 blade I was thinking of going with a 20p 4 blade I'm gonna try to get my wife to see what I have on it

 

[Sean Troy]

Stick with the correct pitch 3 blade for a 90hp. It'll do the job.

 

[Carl S]

I have a '99 pt185 withe a 90 Merc 2 stroke. I run a Mercury Laser II with a 20"pitch. At WOT I get 5200 - 5300 rpm with a loaded boat with 2 persons, full livewell and gas tank. By myself I easily hit 5500 rpm which is max for my year motor.



I tried a Mercury stainless 4 blade stainless but the clutch dog rattle at low rpm was pretty excessive so I went back to the 3 blade Laser II. My whole shot is pretty damn good with all that weight I have when I take my friend fishing. He goes at 325 lbs. and I am pushing 245. ( It's hell to get old, fat, lazy, drink Bud Heavies and eat beef.)



Performance wise I did not see much difference between the 3 and 4 blade props. Might be because it is only a 90 hp



Mercury Laser II Prop number that i have is 48-16990 20P. This one has the Flo-Torq II hub assembly. The original prop on the motor was a Mercury Black Max aluminum 19P with the Flo-Torq II hub adapter

 

[Robert Jenkins 2]

Ok thanks that's what I needed I figured a 20p would be good just wasn't sure about coming out of the hole but I just found a mercury laser 2 on eBay for cheap and scooped it up ill post my results once I get home and get it on my stock aluminum prop was a 21P thanks for all the info

 

[Robert Jenkins 2]

Alright I found out what prop I had it was a stiletto 19p looks like they drilled vent holes in it more then what it had stock changed to the 21p stock prop and with 2 people still WOT was 4500 it would come out the hole a lot better but not getting the rpms any suggestions?

 

[Carl S]

That reminds me, on my previous reply I forgot to tell you that I have all (3) vent holes on my Laser II plugged with a solid plug. Also, the motor is mounted in the second hole(s) from the top. Maybe those extra holes someone added are messing you up. Vent hole locations are very important on a prop for them to work correctly.



Added the link below for more info on prop vents. Don't know if this will help you or not.


http://www.mercurymarine.com/propellers/advantage/technologies/pvs/

 

[Robert Jenkins 2]

So 2nd hole from the top meaning one from being low as it can go? Just making sure because that's where mine is set at now

 

[Dan J.]

It is possible your full throttle range is mechanically impeded under load. Have you checked throttle linkage to make sure you're getting the full range and are truly getting WOT under load? (Not just on a set of muffs, but in a dyno load tank or lake trial.) Additionally, problems with your high speed carb and powerhead electrical system can create symptoms very similar to your description. Just adding some food for thought as your prop and pitch seem within specs for your rig to get WOT (5500-ish), barring any hull imperfections. Let us know. Good luck!

 

[Dan J.]

Also, from your earlier post I'm not quite sure if you're getting the 4500 with the 19 or the 21. I believe the 21 is too much prop for performance in your configuration, but would make a good enough spare to make it back to the ramp if you still have it.

 

[TOMMY RICH]

Depending on the prop...a 21 may be perfect. I'm running a 13X21P SS Quicksilver and couldn't be happier

 

[Carl S]

2nd hole from the top. Yes, there is one hole left before it is as low as it can go. There are five top mounting holes

mine is mounted the with the ones marked X.





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