found this site today.....and put in my info......I may be running the wrong prop. This says I need 13 1/4 x 21. Right now have on 13 1/2 x 15. RPM's with this prop are in range on the top side. I do have the motor pin in the very bottom hole. Have to keep it there to have a decent hole shot. Beagle told me once seemed like I was running pretty deep. Tried moving the pin up and and the boat took forever to get on plane and was a little squirrely. May need to try another prop.Here's my Info.....

MOTOR INFORMATION - BOAT INFORMATION
Motor Type: Drive Outboard Manufacturer: SKEETER PRODUCTS
Manufacturer: Yamaha Model: F-80 STRADA
Model: PRO-75, P75 Hull Material: FIBERGLASS
Year: 1999 Length: 15
Cylinders: 3 Beam: 6 6IN
Spline: 15 Weight: 800
Drive: Outboard Category: Bass Boat
Horse Power: 75 USER INFORMATION
Gear Ratio: 2.00:1 Company: JASON - TURNING POINT PROPELLERS, INC.
WOT RPM: 4500-5500 Contact: JASON FREY
Motor ID: 1893 Boat ID: 164723
DETAIL PITCH REPORT
Search ID: 67414 Shaft Horsepower: 70.567
Boat Weight: 800 WOT RPM Used: 5390
Motor Weight: 228 Hull Type: Bass Boat
People Weight: 336 Hull Coefficient: 225
Fuel Weight: 78 Speed Calculated: 48.932845646282
Gear Weight: 50 Pitch Calculated: 19.174
Total Weight: 1492 Pitch 12% slip: 22.03908045977
# of Engines: 1 Pitch Query1: 21
Altitude: 1000 Pitch Suggested:
HP Loss: 2.250 Pitch Adjusted:
CREATED: 2011-01-21 10:31:02 IP: 85.92.78.167
COMMENTS: NEW

Here's the link .....
Propeller calculator, find the correct pitch prop for your Mercruiser,Volvo Penta,Omc,Yamaha,Evinrude,johnson, or Suzuki