Maybe prop?

[Feustond1000]

ok heres the deal again!! lol this Pontoon has gave me nothing but problems! Ok, i had the carb prof rebuilt new plugs, coils and throttle cable. Here is what she is doing now, When im on the water at half throttle and up it sounds the the prop is coming out of the water, but its not because i have it all the way down. it almost sounds like its spinning out. kinda like its missing out but i dont have any idea! i will be driving and it will just slip and go slip and go. somtimes worse than other times!!! any ideas? thanks!

[badmoonrising]

Sounds like cavitation. Can you post pics of the motor ? Prop should be well below the waterline of the logs.

[HandymanHerb]

Can you say cavitation,: the process of cavitating: as a : the formation of partial vacuums in a liquid by a swiftly moving solid body (as a propeller)

what size prop are we talking about?

[Feustond1000]

cavitation? what would cause this? im not sure of the size of the prop its on a 76 40hp evinrude and the pontoon only runs 10mph..i now the prop isnt the big but im new to all this stuff. i would prob say the prop from the end of one blade to the other is about 8 inches across?

[Feustond1000]

maybe i have it lowered too much? my transom saver actually sits in the water and maybe this could be creating it?? i lowered it down in the water all the way because i thought this is why my water pump burnt up this year?

[BassFrequency]

whoa slow down, no pun intended.

a 40hp motor on a pontoon of about any size aint gonna be a speed demon

we need a pic or 2 to see how the motor is mounted. sounds like somthing is disturbing your props water flow

[HandymanHerb]

Look on the prop, you should find some numbers like 12 x 15 , first one is diameter , second one is pitch.