Getting the right prop for my GSR 2250

[mbhenry1955]

We just took delivery on our new baby and the we are trying to dial in the right prop.


Our dealer is supplying several aluminum props till we get it dialed in and install the stainless.


Any others with the same setup please chime in.


Stats.  GSR 2250 with the ESP package and a Honda 250. 2 people and 15 gal. fuel


1st. prop was a 21 pitch.  We could not hit 6000 RPM's but we hit 45 MPH.


2nd. prop was a 19. with the 2 people we hit 6000 RPM and 43 MPH.   


2nd trip on the 19 pitch with 4 adults and 40 gal fuel and we hit 41 MPH before the prop blew out at 5800 RPM while trimming up.


I believe that if we had a 19 pitch stainless, we might have achieved the 6000 RPM's without cavitating while trimming out.


I really don't want to drop down to a 18 pitch to get to 6000 RPM if the 19 stainless can reach the 6000 RPM goal.


Any ideas or suggestions?


Thanks


Mike

 

[cwag911]

Did you break-in the motor already?

 

[mbhenry1955]

Almost finished.

 

[cwag911]

I would wait till it's all broke-in so then you can beat on it for prop testing. You're gonna like the  Honda. Very quiet and smooth. 

 

[Nautical]

I have the 19 pitch SS on my 2275 RLCP with a Yamaha 250 and your numbers seem very close to mine.  I don't recall the exact top RPM but 5800 rings a bell.  I don't go WOT that often but I'll try it again next time I'm out.  I've been wondering if a 17 or 18 might give me a better top end but like I've mentioned in other threads, it's not much fun going that speed without a windshield anyway.

 

[mbhenry1955]

Nautical,


If I remember my numbers right, if you were to go to a lower pitch (17 or 18) you would loose top end but gain hole shot.


I also know what you mean about the windshield. I now have to wear my ball cap backwards.  LOL

 

[Angela & Michael]

Don't forget you can go 4 blade prop as well! ️

 

[mbhenry1955]

Michael, I have thought about a 4 blade, but I'm not having any issues with hole shot as it launches like a rocket!

 

[mbhenry1955]

Update,


The engine is now broken in.


We went out Memorial Day weekend (needless to say, very rough water)


With 4 people on board, 25 gals of fuel, my top end numbers are good. 40 MPH @ 6000 in rough water.


Now the down side.


At 3000 RPM's, speed about 22 MPH, trimmed all the way down, the engine cavitates going over waves and in turns.


I can see it in the tach, and hear it and feel it.


The engine is mounted 1 hole up (per factory spec) with the cavitation plate 1 inch above the bottom of the keel and the prop is a 19 pitch stainless. Not certain of the diameter.


My dealer is researching the issue, but doesn't have a selection of 19 stainless props to test.


Do we try dropping the engine or try to find a different prop.


I think maybe drop the engine as it is the less expensive test.


Any other ideas.


Thanks


Mike

 

[Angela & Michael]

I'd try dropping 1 hole and trim up for best performance. You may want to check cupping on your prop as well if the problem persists. As for a 4 blade (which I don't use) it will give better bite in the water at all speeds. Your engine will have a great hole shot no matter as it's got the all the horsies you need. Plus a four blade gives more mpg and you lose very little top speed. Keep us posted & good luck️