tower of power loss power

[cuenta619]

What you are seeing is normal when the pitch of the prop is too much. The motor cannot spin fast enough to develop enough power to accelerate (unscientific description).
I would recommend a 19P prop to test.

finally the motor ran with the new propeller 21 p. Stainless steel 46 mph at 4500 rpm same speed with the older propeller aluminum 17 p. 46 mph but at 5800 rpm which is more convenient to save gas

 

[cuenta619]

Which propeller is better to ajust the idle
21 p stainless steel or
17.p aluminum (menor engine load)
And other questions is recommended eliminate the economiser hose in the carb. I hear that needs remove and plugged the fitting

 

[Chris1956]

I never had any issue with the economizer (backdraft) system. Disable it if you wish, by removing the backdraft jet on the carb cover or plugging the hose. You should set idle mixture with the prop you intend to use.

Based upon your observations, that 21P prop will be too great a pitch, if you have anything but a minimal load in the boat. A prop shop could bend it to a 20"P, or you could get a 19P prop.

Also, 5800 WOT for the 17P prop and 4600 RPM at WOT for the 21P prop doesn't makes sense. If the tach is correct for the 17P prop, it should read about 5000RPM for the 21P prop. The loss of 400 RPM is unexpected. Is the 17P prop not cupped? Again, I think you will be overpropped with that 21P prop.

 

[cuenta619]

Also, 5800 WOT for the 17P prop and 4600 RPM at WOT for the 21P prop doesn't makes sense. If the tach is correct for the 17P prop, it should read about 5000RPM for the 21P prop. The loss of 400 RPM is unexpected. Is the 17P prop not cupped? Again, I think you will be overpropped with that 21P prop.[/QUOTE]


if it reaches 5800 rpm with 17 p. Propeller
I think because I don't have the stop throttle screw
Today I'll installed a new one I go trying with a 19 p.
Thank sr.