Anyone have any good ideas?

[bmbecker]

Had a 28' Playcraft bought last year. Came with a 48hp Evinrude and I was sick of ONLY being able to troll slowly. I bought a 115hp outboard used from a guy for about $400 and got it running GREAT. I mounted it up last weekend and put new cables on. Motor mounted very easily and fits perfect. Tag of the boat says, Max HP 120 so I know I should be OK there.

My question starts here though. I took it out and launched it for the first time with different motor on it tonight and took it for a ride around the lake. Ran great. Gained about 10 to 15 more MPH on the water. Bounced up from 14-17mph with the old motor up to 23-30 with the new one...thats pretty good I think for a 28' pontoon. But, here goes the problems...

The only way I can run it is with the trim all the way down. If I trim it up, it revs up the RPMs and acts like it isnt pushing any water and then it bogs it down and take hold and sets you in your seat and then slips out again. Im curious of a few things....

No. 1: Would a whale tail help this out by holding the water down around the prop?

No. 2: Would the fact that there is NO Zinc/Anode trim tab or what ever it is called right behind the prop cause that problem? OR....

No. 3: Could it be possible that I should have gone with the EX-Long shaft to drop the prop deeper in the water?

If anyone has any other good ideas for me....Im all ears. I think I am going to get a "whaletail" on it and of course a trim tab and see if that helps or not. I will say this though....when it was peged and running full out, it ran great, never skipped or nothing. And if you were at a stand still in the water and dropped the hammer on it....the hole shot was pretty good for that big of a boat. It would usually skip out of the water once and rev up but then grab again and take off from there and hold good.

Thanks for your time!!!

 

[5150abf]

Re: Anyone have any good ideas?

No, a tail is intended to lift the hull out of the water, they aren't very effective on pontoons and it sounds like the last thing you need is to be farther out of the water.

The trim tab is for steering and couldn't cause your problem.

I believe #3 is your answer, as you trim the motor it lifts it slightly and it sounds like yours is just in the water but on a 28' toon trim isn't going to make a lot of difference anyways.

Even if you had a longer shaft I don't think trimming it out would have much effect at all, it sounds like the boat runs fine other than it won't trim out but it doesn't really need to on a toon so I would run it like it is, maybe play with props to get your RPMs right.

 

[steelespike]

Re: Anyone have any good ideas?

You might try a 4 blade pontoon dedicated prop.sometimes called elephant ear prop.As suggested trim has little effeect on a toon just try to get the best rpm and speed. Trim range is very limited on a toon.

 

[rrhodes]

Re: Anyone have any good ideas?

I assume you can't just lower the motor?

 

[Silvertip]

Re: Anyone have any good ideas?

It really isn't going to make much difference how low the engine sits. The angle of tilt means the prop is pushing water to the surface since the engine cannot raise the bow of a pontoon like it can a "V-hull". If the bow were to rise, then one could continue to add trim. The idea is keep the prop shaft parallel with the water. Positive trim setting while still keeping that parallelism is very limited with a pontoon. As mentioned, a pontoon prop may allow a little additional trim but I wouldn't expect enough improvement in trimability to make it worth while. It will likely improve performance a tad however.

 

[DMAN1968]

Re: Anyone have any good ideas?

When I first got my 24 foot Lowe's it had a 48 hp johnson on it with the doelfin/whaletail. I had some problems with the same thing that you describe but without the trim. I took the doelfin/whaletail off and the problems became much worse, when I put it back on it was back to only every once in a while. I can't say why but for my boat with that motor the doelfin/whaletail definitely reduced prop blowout.

I eventually changed it out for a 115 hp and have never had that problem with this motor. I did try a whaletail on the 115 once just to see what it would do. It actually pushed the bow too low in the water. Since I still have no trim with this motor I took it off.

Mount the motor lower on the transom, make sure it is propped right and also make sure the weight is balanced correctly on the boat. Too much weight in the front made my prop blowout problems worse as well. If those actions don't correct the problem then a whaletail/doelfin is an inexpensive and easy possibility.

 

[tashasdaddy]

Re: Anyone have any good ideas?

i have a 50 on my 20' cannot trim out. actually t n t is a waste on my boat, other than trailering.

 

[Rancherlee]

Re: Anyone have any good ideas?

Trim makes a bit of difference on mine. It really depends on the angle of the Transom/Motor pod. My motor trimmed all the way in has the propshaft pointed at the floor of the pontoon roughly 1/2 down the boat and has to be trimmed quite a bit to get it parallel with the pontoons, about 1/2 on the trim gauge. Mine too would blow the prop out at anything but fully trimmed in SO I dropped the whole motor pod down with 2x2x1/4 aluminum tubing for spacers along with longer STRONGER bolts and bigger washers. No I can trim it to parallel AND I picked up 2mph.