what should happen ?

[sun burn]

ok my tac dont work first off. got one on order...got a turbo 14 1/4 dim. x 20pitch prop was on the boat.changed it out with a quicksilver 12 something dim.(went smaller) with a 21pitch. what should happen more hole shot and higher rpms at wot ? i got a gernal idea of the rule on pitch size but what dimator size?
with a full boat its kinda of sluggish pulling the tube with the turbo prop but just cruising it does good just tiring to get more fun out of tubing and skiers up. thanks

 

[Scubaproh20]

Re: what should happen ?

opposite an 18 or 19 would do that a 21 will be lower rpm and possibly higher top speed if your boat has the power

 

[sun burn]

Re: what should happen ?

so the smaller diameter wont effect the rpms ?

 

[steelespike]

Re: what should happen ?

I would worry about the 12 "something" fitting right.The hub may not fit the exhaust passage or the gearcase of the leg.Would help to know what motor and boat.Was the prop listed for your application?
If its a 2" change in diameter yes assuming it works it would raise the rpm.Using the diameter
as the primary source of rpm is like using the wrong end of the paddle because you can move it through the water faster.

 

[SparkieBoat]

Re: what should happen ?

you need to get your tach installed first and to a WOT test and see what you have. then we could tell you what prop would work for you.

 

[sun burn]

Re: what should happen ?

had a 20 pitch 14 1/4 dim. turbo prop run at 3600 rpm put a quick silver 21 pitch 12 something diameter its stamped but in code or something getting a little over 4100 rpm water real ruff white capping only held wot for few sec.s........going to get better reading in calmer water

Would help to know what motor and boat.Was the prop listed for your application?
the 21 pitch came off of a 1980 something 80hp mercury outboard.
put it on a 1983 16ft baretta120 murcrusier alpha 1

 

[SparkieBoat]

Re: what should happen ?

I would try a 17 pitch 14 something dia prop. see what happens. see if you can borrow a used one from a boat repair shop. (with a deposit of course).

 

[Bondo]

Re: what should happen ?

Would help to know what motor and boat.Was the prop listed for your application?
the 21 pitch came off of a 1980 something 80hp mercury outboard.
put it on a 1983 16ft baretta120 murcrusier alpha 1

Ayuh,... Didn't you notice the barrel of the prop is considerably smaller than the outdrive gearcase,..??
Doesn't it ventilate to beat 'ell,..??

Just because a prop will slide onto the shaft,...
Don't mean it Fits...

 

[SparkieBoat]

Re: what should happen ?

I was wondering how he was able to use a 12 dia prop..LOL that prop is no good for your set up.