22' Sun Tracker Pontoon: 25" Shaft OK?

[Dennybot]

Hello all. New pontoon owner here, and I have a few questions as I get to know the boat:

Boat: 2007 22' Sun Tracker Regency
Motor: 1998 Mercury Offshore 150 25" (carb)
Prop: Aluminum 3-blade 14.8-Dia 17-pitch

My main question is:

1. Is a 25" shaft motor appropriate for the boat? I can't find a clear answer on my own.

I ask because we're not getting a good RPM range at WOT, and before I start experimenting with props I'm wondering whether we might want to consider raising the motor with Jack Plates.

We've taken her out a few times, and based on documentation for my motor here on the iBoat forums, it looks like we should be getting 5000-56000 RPM at WOT:

http://boatspecs.iboats.com/Mercury__150XL_Offshore_2.5L__150hp__1998/bpe/57e16405

However, we're only getting around 4500 RPM at WOT with around 600 pounds of people on board.

Any advice on how to dial things in? Jack Plates to raise the motor? Or should I focus props?

This is just for leisurely lake and bay cruising. I don't need a hopped-up ski boat. I actually wish we had a smaller motor, as the 150 is pretty much maxed out for weight and power on this boat.

 

[Jeep Man]

Re: 22' Sun Tracker Pontoon: 25" Shaft OK?

My 20' Merc is one hole from the top, meaning it is as low as it will go. Any lower and the steering arm hits the deck. I would think that if yours was mounted as high as possible without a jack plate it would be close to mine. What prop are you running? I would consider lowering your prop rating by 2p and see where your at. You may have to drop by 4p.

 

[5150abf]

Re: 22' Sun Tracker Pontoon: 25" Shaft OK?

With the water behind a toon being so turbulent I don't think I would mess with a jack plate and just concentrate on a prop instead.

Toons are kinda funny ans don't respond to the same things that mono hull boats do.

Get into the prop section and get advice from them as to what to get.

Are we certain the engine is running right, you can't prop out a bad cylinder of plugged carbs.

 

[The Rooster]

Re: 22' Sun Tracker Pontoon: 25" Shaft OK?

Denny, while cruising, is your cavitation plate above the prop running about level near the surface? Do you have any room to raise the motor w/o a jackplate? All barges are different, but that prop sounds about right. Any way to verify if the tach is reading correctly? Good luck !!!

 

[rhinoronnie]

Re: 22' Sun Tracker Pontoon: 25" Shaft OK?

Hi
i have a 21 fishing barge with a 90 optimax 25 in shaft with a 14.25 x 12 pith prop and iget 5400 rpmgreat hole shot with 6 people on board tops out at 26mph

 

[Triphammer]

Re: 22' Sun Tracker Pontoon: 25" Shaft OK?

I've got an 87 Lowe 20 "Fish & Fun" w/ an 87 125 Force. Can't seem to get decent WOT. I'm running a 13 3/4 X 15 alum prop. The motor has a 25" leg so first thing I did was to build & install a jack plate to take up 8" & get the cav plate level with the bottom of the motor pod. It gained me about 200 rpm to 45 or 4600 & the hole shot is better than before, almost great.The cav plate still isn't visible while running about 22 MPH but I don't think I can raise the motor any more as it cuts loose in hard turns.
So, "25" motor ok?' Nope but there has to be other issues.

 

[Dennybot]

Re: 22' Sun Tracker Pontoon: 25" Shaft OK?

Hey all... I'm attaching an image to show where the cavitation plate is in relation to the motor pod. Looks like it's just a bit lower than to bottom of the pod (transom?).

Does this look... OK? Acceptable?