[R H Cotton]

Earlier I had posted a thread about my pontoon prop not getting enough rpms. I was getting 4800 rpms. With several good suggestions I raised the motor one notch. Now I am getting 5350 rpms at wot. My boat is a 20 ft. pontoon with a 75 E-Tec and a 14x11 prop. If I were to raise the motor one more notch and not get slippage and the rpms were to increase to above the maximum 5500, would it be more economical as far as gasoline and increased speed to put on a 14x13 prop? Once again I appreciate all help and suggestions.

[steelespike]

What is your speed?
If you can get another notch go to it. I think you are about there as far as ventilation goes.If you make it the prop change will depend on your results.
If you need less than 2 inches pitch
you could get the prop repitched.Any time you can get less motor in the water it has to help.

[R H Cotton]

My speed with the 14x11 at 5350 rpms is 20 mph.

[steelespike]

It seems from the Etec tests I've seen that your prop will be in the 13" range when you are set up right with a speed around 21-22 mph.
Unfortunately there are no pontoon tests for your motor.
As I said before the 50 pushes a 24 ft toon at 19.5 mph with a 14/13 at 5,375
and a 21 ft at 21 W 13 3/4 X 13 at 5,500. the 50s max rpm is 6,000. and your 75,range is 4,500 to 5,500.I would think if you can hit the setup just right you would be in the 22+ range with at least w a 13' pitch.