14' Valco 15 HP Evinrude prop suggestion

[davkrat]

First post here. I have a 14' Semi v with a 1977 15hp 2 stroke Evinrude. Primarily used to kokanee troll on reservoirs in California but I want to use it to get in to some duck hunting spots on slow small rivers. Contemplating getting a small longtail for it but most of the waters I might use it in my outboard can probably get me in to 90% of the spots. It currently has a 9.5" x 10" 3 blade on it which has seen better days. I'm hoping to get a little more top end for scooting around the reservoirs between fishing spots so I will probably get another 9.5" x 10" or maybe an 11" pitch.

For shallow water river stuff I was thinking maybe a 4 blade 9.25" x 8" might be good to hop up on plane quicker. Don't need the top end speed but staying up with a heavy load would be desirable.

Never really played around with prop style or size always stuck with the stock recommendation. At $70 for an aluminum it won't kill me to experiment a little bit. Any advise would be appreciated.

 

[Gotem]

I have a 70's 15 hp Johnson. I had a prop with a pitch of 10 witch was running around 5400 rpm so I tried a prop with a pitch of 8. The rpms went to about 6200. Yes I did gain a few extra miles, but it also increased the noise level so much that I switched back to the original prop.

 

[davkrat]

Running the stock 10 pitch prop I'm getting 5050 rpm at WOT for 15 mph with myself, two kids and fishing gear. That's around 25% slip! Going to order the 4 blade 8 pitch tomorrow and see how it works.

Afraid I'm overworking my motor running it that inefficiently at low RPM's. Might not increase top end but I would not be surprised to see some increase just based on how poor the current prop is performing but hopefully see more consistent performance between light load and a heavy load when my brother decides to tag along.