Stock prop vs custom prop

[tyst67]

I have a 15 pitch stainless ballistic and 17 pitch stock prop. I go 41.7 mph with the stainless and 38.5 mph with the stock. This tells me that the 17 is too much prop for my 40hp mercury motor (I think?????). My boat is 14 feet long and only weighs 100 pounds. How would changing to a higher pitch chopper prop give me more speed if changing to a higher pitch stock prop slows me down???

I should mention my motor has awsome bottom end. It gets to 41.7 mph really fast. I thing it should get a few more mph top end.

[stokernick]

what rpm's are you turning?

[tyst67]

The motor specs say they are between 5000 and 5500. I don't have a tach yet but i am getting one.

[Fuzzbutt]

Well having an accurate tach is paramount to knowing what is going on with your motor.

If your 15" ballistic is pushing you to 41.7MPH I don't think it is too much prop for you. It is certainly faster than the higher pitched prop you call your stock prop.