tried 3 props, same results

[gramps]

I have the new Mercury 150hp 4 stroke on our Berkshire tritoon and we love it. I have one concern though, I'm not getting 5,800 rpm's just 5,150 at WOT.
I have tried the following 3 props with the same exact results.

4 blade 15 x 15 ss Revolution by Mercury
3 blade 14 1/2 x 15 ss Vengeance by Mercury
4 blade 14 1/4 x 13 ss by Turbo
The dealer supplied the 4 blades and I bought the 3 blade.
I'm surprised that the results all have been the exact same, the 4 blades gave the same mph at 3,000 & 4,000 rpm's and at WOT

Mercury shows on their web site that most toons that they try this motor on get 5,600 to 5,800 rpm's with 35 to 39 mph. I hate spending over $500 to only find out that it may be the same as the other 3 props.

What are your thoughts, the dealer doesn't want to try a 3 blade so it's up to me to figure out. I'm very satisified with the handling and everything else with the Revolution prop but wonder if I'm losing out on more performance.

[The_Hellbilly]

Have you checked your motor height?

[jrolin1]

Have you checked your motor height?

X2! I bet it is too low.

[gramps]

When I run I can see the skid plate, so I think it's ok. I'll double check it though.

[Texoma Toon]

If you haven't already you might try to trim it up a little higher. Just before it blows out. Any rooster tail should be no higher than the engine.

[Bamaman]

Gramps:

I've noticed that they're using the Merc. Enertia prop (15 pitch) on most every Mercury 150 engine pontoon boat test (online.) I cannot remember seeing any 4 blade props in any magazine or online pontoon/tritoon boat test.

My next door neighbor's Harris Classic 240 with a Verado 150 is pushing a 14 pitch Enertia prop.

The new Fourstroke engine has the reputation for being a strong motor, and I would think a 15 pitch prop would produce more rpm's than you're seeing.

I too think your engine is running too low, and needs to go up a couple of notches. It's very difficult to experiment with props if the engine is plowing through the water. If you got any ventilation after raising the motor, just drop it down a notch.

My new Yamaha 150 on a 24' Bennington SSLX has a 14 pitch prop, and I'm up against the rev limiter @ 6200 rpm's. It's in the second notch, which puts the motor about 3/4" above the transom. The dealer's switching out to a Reliance 15 pitch prop this week, which appears to be my best pick.

[Smoky Mountain]

Interesting on being mounted too low.
I'm going to have to look into that.

My Bennington 22 with 3 toons and the express performance package powered by a 150 Yamaha turning a 15 1/4 x 15 with a light load maxes out at 5400 and 34 mph WOT.
I'm looking to get more towards the 58-6000 range.
Dealer said he will work with me to get it propped righ but he claims that's what Yamaha recommends....I would agree in theory but the performance doesn't bear it out. I tried various trim levels, but I didn't check the height and this rig sets way low in the stern.

[Bamaman]

Smoky:

Is your engine mounted down on the transom? Mine is up in the second notch--3/4" above the transom. My Middle TN dealer intended to put a 15 pitch Reliance prop, but slipped me a 14" when he ran out of 15 pitch props. I can barely plane out @ 3000 rpm's with a 24' SSLX model with Express Tube and just the strakes on the middle toon. It easily gets the nose up, however.

Your motor might need lifted a little.

Getting 4 stroke motors broken in the first couple of hours is a pretty boring proposition. I'm in the 3rd hour now, but have been held up with the bad weather this week.

The Knoxville dealer shot me a good price--after I made the deal with my dealer. He was the only one around with the boat I wanted. But, it wasn't worth $1,000 to deal 290 miles away. That's a lot of driving, and a risk if there's any problems.

[Bryden24shp]

The outside temp and humidy has alot to do with the performance of our outboards. While in the 100 degree heat at the lake, I lost 600 RPMs. Dropped from my 19 Mirage to my 17 Enertia. Gained back 200. Running at night, when cooler, I was up to 6600. My Etec was the same when hot out. May be a factor with your, Gramps.
Bamaman, I agree 100%!

[STEVEBRENDA]

The third part of the prop equation is also how much they are cupped. Some of the newer props are cupped mroe than the standard prop.

[rsmith]

First. See if you can find a dealer who will let you test more props. Second. Give a 14p Enertia prop a go. I first tried a 19p vengeance and was low on my rpms. Dropping to a 17p entertain got me about 800 more rpm and more speed. Note: I run at almost 6k elevation so I lose some power due to the thin air.