Anyone run Quicksilver prop on their Yammie?

[SBH2OMan]

I've got a 15p Powertec prop on the Ox66 250 and it seems like the motor is turning very fast at cruise and using a deeper pitch I could get better fuel economy at cruise. With the 15p prop, the best she will do is about 13gph at roughly 19-21 knots and turning 4600 rpms which based on things I see from other people is like driving around in 3rd gear instead of 4th (or 5th).

Holeshot with the 15 seems pretty good - without having to firewall the throttle, she'll get up on plane in 5 seconds or so (though the transition is pretty subtle in this heavy boat and deep vee hull...)

I can get a SS Quicksilver prop in a 17 for about $200 and I'm thinking about trying it out and if it doesn't work out better (but still good enough) I will then keep it as a backup prop for emergencies.

 

[Bryan 2530]

Is 4600 your WOT??

If so going up in pitch will bring that down, those numbers don't seem right.

Is the prop on there a 4 blade and the merc a 3 blade?

Need more info.

17 pitch is about right for a starting point, but what is the top RPM?

 

[SBH2OMan]

Is 4600 your WOT??

If so going up in pitch will bring that down, those numbers don't seem right.

Is the prop on there a 4 blade and the merc a 3 blade?

Need more info.

17 pitch is about right for a starting point, but what is the top RPM?

No, sorry. 4600 is where I seem to get the best speed vs gph ratio.. WOT is like 5500 or 5700 but I have not run her flat-out in calm seas for long enough to see if she is really topping out there.

Current prop is 3 blade. Merc QS is a 3-blade.

Looking to optimize cruising speed/MPG. (maintain same gph but increase cruise speed). She seems under-propped, but I don't have much to compare to.

 

[Bryan 2530]

Sounds like you are on the right track. $200 is cheap, is it used?

I would do it if the prop is in good condition.

 

[SBH2OMan]

I'm assuming it is used but according to seller it is "polished and balanced"

 

[John_Madison CT]

I run the Merc Mirage prop on my 250hp Ox66. The hull is the 2520DV, single engine.

I turn 5300RPM's WOT with a 17" pitch prop.. The Ox66 engine has a WOT RPM spec of 4500-5500RPM's. I know, sounds crazy, but you can them listed. I use the upper end.

I think you can go to 17" pitch, gain speed at the same RPM, improving your fuel economy.