Prop Help

[NoleFear]

Need help on prop or I'm I close to right. '93 Hewes 115 Yamaha V4. Mounted 2nd hole from top.

Had a jack plate but removed it...too many problems

Old Prop 3 blade 19" (or so it says) I thinks its just worn out or has been modified.
6500+ rpm (no trim)
WOT 40mph
Good hole shot (no tabs)
Blows out in turns and with any trim. Feels like it slips alot.

New Prop 4 blade 17" Turbo IV
5200 rpm (no trim) with trim can get 5600 - 5800
WOT 40.5mph trim 41-42mph
Hole shot not as good as with 3 blade (no tabs)
Very little blow out in turns
Good grip

Do you think I need to go to a 15" 4 blade to get a better hole shot and more RPM's?

[Barhopr]

sounds like good numbers to me. lack of cupping may be the dif. in hole shot. But then again, what do I know.

[Jumptrout51]

I think you need to just go fish and quit worrying about how fast you get there or back from there.
If someone is trying to beat you to a fishing hole,let them have it. If you don't have more than one fishing hole, speed is not your problem.

P.S. one day you may even quote this statement.

[NoleFear]

Just trying to get away as quick as I can from the slow/crazy old drivers on the big pond

Just to clarify I'm trying to reprop after removing the Jack Plate. I always ran with the JP half to full down and the rpms were always in the motors upper range 5500-5800. The motor is now fixed mounted and my rpms were/are to high and have blow out issues with the 3 blade. About 3/4 trottle was 5500 to 5600 rpms.

[Barhopr]

http://www.go-fast.com/Prop_Slip_Calculator.htm
try this. It should tell you if you have a slipage problem with your prop. May not be the answer but it may help you get there.

[tin can]

New Prop 4 blade 17" Turbo IV
5200 rpm (no trim) with trim can get 5600 - 5800

Do you think I need to go to a 15" 4 blade to get a better hole shot and more RPM's?

If you're turning 5800 you don't need to drop in pitch. Most likely, if you dropped to a 15, you would turn over 6000.