motor depth on 24ft pontoon?

[pontoonboy1]

i have a 24ft float boat with a 80hp mercury longshaft on it, how deep should my prop be in the water? not power tilt/trim. thanks alot, is why i wonder is the motor is not "pushing" as well as it should but more like plowing and it is tweaking the floor a bit if you give throttle fast, i have a all aluminum transom that looks like a big V if you were to take it off the boat and look down at it, again thanks

 

[Pontoonfoon]

Re: motor depth on 24ft pontoon?

as far as actual depth... not trim

when running WOT with just you in the boat, the cavitation plate should be just at the surface. or just a tiny bit below any deeper than that and your just dragging extra motor.


on mine i start out with her trimmed fully down and then as I throttle up i bump her about 2 seconds of upward trim and she runs perfect. (21" party barge 90hp merc)

 

[5150abf]

Re: motor depth on 24ft pontoon?

I am more worried about your floor being tweaked than how the engine runs.

Elaborate on exactly what that means, the floor should not move AT ALL under and load or throttle and you may have a serious problem with your boat.

I woudl get under the boat and inspect all the bolts to make sure nothing is loose, again if the floor is moving there is a serious problem.

 

[pontoonboy1]

Re: motor depth on 24ft pontoon?

the floor is not moving much, my problem is i have a longshaft motor on and if you gun it, it has so much power and way to much motor in the water that it is plowing, i checked the transom and nothing is bent, i have decided after doing alot of searching to make a jack plate and replace the prop, it has seen better days, i think if i get the plate level with the v on the transom that it will push instead of plow

 

[rburch2003]

Re: motor depth on 24ft pontoon?

I have a 2006 24 ft. Premier Pontoon with a 90HP Evinrude ETEC. I start out with the trim all the way down and bring it up slightly as I speed up. As I adjust the trim not far from fully down, I am experiencing cavitation.

The Dealers answer was just put the trim down.

Any thoughts?

 

[EGlideRider]

Re: motor depth on 24ft pontoon?

An 80 on a 24 foot boat is certainly not too much power. Before doing anything, you should compare the water around your motor to that of other pontoons. I'm betting that your turbulence is normal. But if you don't think so, you should first manually raise the tilt to look for an improvement. If that does not produce desirable results then raise the motor a couple of inches at the time until ventilation occurs. Then lower the motor down to the next hole.

 

[lmuss53]

Re: motor depth on 24ft pontoon?

Pontoonboy, Egliderider's advice is right on for your issue, move the motor up by the mounting holes a little at a time to see if your issue gets better. If you move it up 6 or 8 inches at once with a jackplate you will blow the prop out right away.

rburch, welcome to iboats, you should start a seperate post and list a little more information about your boat, like the wide open throttle rpm's and the current prop size, you may have a prop issue. Be careful with that dealer, he should be trying to help you resolve your problem, not giving you BS answers like he is.