smaller dia same pitch

[night moves 11]

this is what i get with a 15 x 17 on my wellcraft 22 wa 200 johnson 2000. wot gives me 5400 rpm 41 to 43 mph depending on wind and current. i would like it to be closer to 5800 rpm ,6000 is max. if i have the prop turned down to 14 3/4 x 17 will i see the increase in rpm that im looking for?

 

[Bondo]

Re: smaller dia same pitch

Nope,.....

Changes in Pitch will change the rpms,..

Diameter has very little to do with it,.. It's more a function of blade Design...

 

[steelespike]

Re: smaller dia same pitch

Tell us a little about your prop;Aluminum?(usually painted)Brand/model?excellent condition?Cupped?Is the motor well tuned?How is the setup.The antivent plate(just above the prop) even with the bottom of the transom is considered a starting point for motor height.Raising the motor could give added speed and rpm.Be sure it pumps water.You might read up on "Turning Point" props.A prop like it could allow even more height and an overall performance improvement.Always make only one change at a time.

 

[180shabah]

Re: smaller dia same pitch

Turning Point is a good option(after we figure out what you really need of course). I have a hustler that I run when I can't "afford" to run my shifting prop. The difference between it and Merc's black max prop is nothing short of increcible. For the same money as another black max I got improved holeshot, higher top speed, and MUCH less blowout in sharp turns. The only downside - it's not as pretty as all of those $400 SS props. I chose to sacrifice the extra "cool points" and save my money for gas....

 

[Woodnaut]

Re: smaller dia same pitch

NM11 - Is there any cup on the prop that you are currently running? If there was you might gain some RPM by eliminating the cup.

 

[night moves 11]

Re: smaller dia same pitch

the prop is a michigian wheel 011007 15x17the engine is mounted with the cavitation plate about a inch and a half above the v of the hull. the transom is 28" the johnson model j200vxsss is mounted as low as it can go. what gets me is the wellcraft specs state 48 mph @ 5880 rpm with a 14 1/2 x 18 micigian raker.i have less pitch and get less rpm. iv'e only had the boat for one season.i had to do a decarb and picked up 200ish rpm and 5.6 mph . its only been run at wot 3 times sense decarb maybe 10 mins each trip. could it still be gummed up?

 

[coolguy147]

Re: smaller dia same pitch

idk that rpm sounds good. what was ur load like? if ur reaching that rpm doesnt soudns gummed up to me. so my opinion i would go to stainless maybe? get a few mphs. then keep the other prop as a spare for emergencys

 

[Dhadley]

Re: smaller dia same pitch

A Raker is an OMC / BRP prop, not a Michigan. That prop has a fair amount of lift and probably not fair to compare it to a standard Michigan prop. Reducing diameter and / or pitch simply to gain rpm will almost always decrease efficiency.

At a true GPS 42 mph and 5400 you're at about 11% slip which is not bad. Basically that prop is doing a pretty fair job for what it is. An 18 pitch prop on that motor turning 5880 and 48 mph is about 11-12% slip. The difference is going to be in the style of the prop and how they tested it. A prop with more lift will have less hull drag and therefore be faster.

 

[night moves 11]

Re: smaller dia same pitch

i guestamate the boat loaded weigths about 4250 lbs . i logged all speeds from the gps. she gets up on plane at a five count which seems pretty responsive to me. i,m not ready for a ss prop yet because i,m just to new to aboat this size and worry about hitting somthing on the bottom while out exploring.probably for the 2010 season i,ll try a ss prop. one other thing is i get 2 mpg.

 

[steelespike]

Re: smaller dia same pitch

i guestamate the boat loaded weigths about 4250 lbs . i logged all speeds from the gps. she gets up on plane at a five count which seems pretty responsive to me. i,m not ready for a ss prop yet because i,m just to new to aboat this size and worry about hitting somthing on the bottom while out exploring.probably for the 2010 season i,ll try a ss prop. one other thing is i get 2 mpg.

A 200 would use about 20gph(gallons per hour)at wot(wide open throttle.)you get 41 mph thus 2mpg.
Pushing 2 ton to 41 mph seems pretty good to me.Improving your speed
should improve your mpg.But even at 48 I think you can see your still in that 2+ mpg.If you play with your cruising speed you could get signifigantly better mileage.Usually the best cruising speed is between just planing and about 2,000 rpm higher.You can improve your mpg with careful prop selection,motor trim,weight distribution and trim tabs.You might check out the turning point "Rascal" or "Hustler";give close to stainless performance at Aluminum prices.

 

[180shabah]

Re: smaller dia same pitch

....You might check out the turning point "Rascal" or "Hustler";give close to stainless performance at Aluminum prices.

Legacy, not rascal. The rascal is for small OB's, under 35hp.

The legacy is the same prop as the Hustler, but it uses the same hub as the Mercruiser props so it would be a better choice than the hustler unless you find a great deal on the hustler.