I am think about adding a doel-fin or SE hydrofoil to my mercury 150/Ranger 373. The boat has trouble getting on plane when tournament loaded.

Anyone have any pro's or con's?

It should help, but first make sure the problem is not the wrong size/pitch prop.

I had that same problem getting on plane with my Z7 with a 150 Merc, and a larger prop with more pitch solved it. 

With the original (wrong) prop the engine would turn up nearly 5000 rpm, but struggle to get on plane.  With the new prop, the engine only turns just over 3000 wide open throttle to get on plane.

With the first prop the engine would over rev once on plane and motor trimmed.

If you have a three blade prop, changing to a four might help.  Check with a Ranger dealer.  They should know the correct prop for your rig and load.

Is it possible the motor needs a tune up, new plugs or whatever?  There are many factors to consider, including weight distribution in the boat, and motor trim.  Do you have the motor trimmed all the way down when taking off?

Some of these are obvious to many, but I do not know your level of experience, so I tossed them out there for your consideration.

The boat is using a 22P Michigan 4 blade prop. It runs 60 mph @ 5800 RPM. It has a small hub to allow for the motor to spool up instead of vent holes. It will not spool up. It labors to push over on plane. (Yes, I trim the motor all the way down. I have owned 3 boats and have boating for 20 years.)It works ok until I have full gas tanks(24 gal), full rear livewell, 2 people, plus the 3 batteries in the rear during tournaments. The boat sit low in the rear because of the designed weight distribution. The motor is in good health, although it is 1984 2.0L. It is serviced and compression tested annually. I do not feel that the motor is the issue. In addition, at mid range speeds the boat like to porpoise and I have to trim the nose way down.

Thanks Rhino

It sounds like you are a candidate for the fin.  I don't know what your engine should turn wide open.  Mine runs about 100 rpm less than the recommended max.  I want to say 6300.  My Z7 does just over 58mph, fully loaded.

Your setup sounds similar to mine.  Three batteries and the oil reservoir behind the live well.

I am going to try to get a bit more weight forward if possible, and stow lighter gear in the aft storage compartments.

The motor WOT is supposed to be 5500 but all the Mercury guys say that the 2.0L 150 can run up to 5800 as long as it is properly lubricated(pre-mix) and not over heated (I have water psi and water temp gauges).

I actually ran the motor up to 6800 rpm once (wrong prop) and she held together quite well.

Some guys swear buy the doel-fin and others despise them for slowing their boats down and the weed accumulation. Since holes will have to be drilled in the cav plate, I am just trying to find out as much info as I can before I blow $60.

I would look to various options in props prior to drilling into the cavitation plate. 

Treat the cause of the slow planing/poor performance not the symptom.

The motor WOT is supposed to be 5500 but all the Mercury guys say that the 2.0L 150 can run up to 5800 as long as it is properly lubricated(pre-mix) and not over heated (I have water psi and water temp gauges).

I actually ran the motor up to 6800 rpm once (wrong prop) and she held together quite well.

Some guys swear buy the doel-fin and others despise them for slowing their boats down and the weed accumulation. Since holes will have to be drilled in the cav plate, I am just trying to find out as much info as I can before I blow $60.

One of the brands make an adapter where you don't have to drill holes in the cavitation plate. I personally went with a doel-fin and it dramatically improved my time to plane in my Carolina Skiff J16 w/ 30HP Tohatsu 4-Stroke.

The Dania Beach Marine Flea Market is right around the corner, Kevin.  I believe it's the 17th-20th of this month.  You may be able to find a Doel-fin that fits there.  Or a different prop if you're looking for one.  I went last year and was blown away at the amount of stuff there.

The Dania Beach Marine Flea Market is right around the corner, Kevin. I believe it's the 17th-20th of this month. You may be able to find a Doel-fin that fits there. Or a different prop if you're looking for one. I went last year and was blown away at the amount of stuff there.

Thanks

Do you want to check out the flea on that weekend?

Go with the SE Sport 300. The first time the Doelfin bites the water during a hard turn and you finally get that crease out of the seat from the butt pinch, you will wish you had gone with the SE. Besides that, while both are funky looking, at least the SE looks a lot better.

If it's vented properly, you should be spinning up to about 4,000 rpm so the motor can get into it's peak torque band. If not, you might try not tucking motor all the way in, leave it a couple of degrees short of fully tucked and see what it does. Might even try raising the motor some, it may be too deep in the water.

Personally, I've never thought much of Michigan Wheels. Strickly a low performance prop. If you can get you're hands on a high rake, SS merc prop, see if they will let you try it.

Years ago, I bought a used 335 Commanche with a 130hp Yamaha that had many of the same issues.  A sluggish hole shot and at times it hopping like a frog.

The previous owner had installed a Doel-Fin on it which did help the hole shot, but didn't do a thing to cure porposing.  It took a new prop to cure that problem.

If you can find a prop shop or perhaps a mechanic from your local marina to help you out.  When I did it, I had a mechanic from West Michigan Wheel go with me right to the lake along with a selection of three or four props.  We tried each one out, and found he one that gave me the best performance.  I gave the shop enough cash to cover the cost of the prop before hand, and paid the mechanic out of pocket for his help.  I also knew that if I damaged one of those props it was coming out of my pocket.

All in all, it gave me the chance to work with someone who knew a lot more about such things as I did, and the company got a sale.  I thought everyone won.

Many years ago I had a bass boat with a Johnson GT 150 (heavy motor). I used to fish tidal water a lot and didn't want to idle many yards to get in water deep enough to take off. I used an Attwood fin which is not flat or cupped, it was angled upward. I think they are still made. That allowed me to get on plane in shallower water and saved a lot of tournament time.

I could also run a lot slower and stay on plane when conditions warranted.

It didn't affect top end speed since most of it was out of the water then.

Go with the SE Sport 300. The first time the Doelfin bites the water during a hard turn and you finally get that crease out of the seat from the butt pinch, you will wish you had gone with the SE. Besides that, while both are funky looking, at least the SE looks a lot better.

If it's vented properly, you should be spinning up to about 4,000 rpm so the motor can get into it's peak torque band. If not, you might try not tucking motor all the way in, leave it a couple of degrees short of fully tucked and see what it does. Might even try raising the motor some, it may be too deep in the water.

Personally, I've never thought much of Michigan Wheels. Strickly a low performance prop. If you can get you're hands on a high rake, SS merc prop, see if they will let you try it.

LOL

The Michigan prop was not my first choice. I also have a Laser II 23P, and a Tempest Plus 24P. The Laser just spools up like a nitro dragster with all the holes plugged, top speed is less (55)than the Meichigan. The Tempest Plus is an older used prop, not bent or dinged, but the prop is suspect to me. The motor would labor would barely push over on take off. Top speed 55 MPH.

I tried different tuck degrees, there is a sweet spot that for my boat is not fully tucked. I use that one.

The motor height on my Ranger is peculiar. Right now I am 3.5" below the pad. If I raise the motor higher, I start to lose water pressure. The hull lift in the stern as it plans off, lifting the water pick up holes out of the water. I was told I could block off the 3 top inlet holes, but I am reluctant to do that. I could install a low water pick up to allow the motor to be jacked up to the maximum height. I am giving this more serious consideration.

I am using a 6" manual jack plate.

I think I will take the prop advice first and try to dial it in with a better prop. Then the low water pick up.If I cant do any better, I might pick up a 21P 4 blade for those swampy areas that fast take off is critical and top speed isn't.

The doel fin or se300 will probably catch more weeds making the situation worse. The lakes in south Florida are shallow(2-3') and thick with submerged hydrilla.

Thanks to all.