Yep, another thread asking advice on props!
Been doing some on-river tests with our 16' Aluma Weld Xpress jon with 25 4-stroke Yamaha. I got the Tiny Tach from Cabela's (someone previously pointed that little gadget out on a past thread-thanks!), my hand-held GPS and here's what I found (boat loaded with 2 guys (about 460 lbs.) fishing gear, small cooler, 6 gallons gas; also have Mac's River runner guard on lower unit of motor):
9-7/8 x 9 prop: WOT @ 5900-6200 RPM's yields 17 mph going upstream (Kenai river)
" @ " " " " 22 " " downstream " "
9-7/8 x 10-1/2 prop: WOT @ 4900-5100 RPM's yields 15-16 mph upstream
" " " " " " 22-24 mph downstream
Question: does someone know what the ideal RPM range is for this motor (tiller, short shaft, 2002 model)? Not sure but I think the 9" pitch prop is winding out the motor too much, but the 10-1/2 " pitch prop is not letting it get in the correct RPM range; can anyone recommend a prop in the middle? The boat loaded is pretty typical.
The 9" pitch prop launches the boat on plane quicker while the 10-1/2" pitch prop takes a little longer. I'm pretty happy with the motor as it uses about 1.3 gallons per 12 mile run (approx. 40-50 minutes) WOT; this is 6 miles upstream & 6 miles downstream.
I called River & Sea today to see what other props they have in stock, currently none.
Any help would be really appreciated.
SIDE NOTE: The Tiny Tach was super simple to set up & use, highly recommend it.