Pontoon Boat & Deck Boat Forum

Since I've had my boat (purchased new Sept. 2017), the analog tachometer has always read right at 6,000 RPM at WOT, which is right where it should be. Top speed was about 38.5. I added a NEMA 2000 network and the Yamaha engine interface so I could get more engine data on my Simrad chartplotter. To my surprise, the RPM reading directly from the engine at WOT is only about 5500, which is significantly lower than it should be.

I gave my dealer a call and he immediately agreed the WOT RPM's were lower than they should be. The boat came with a 16 pitch stainless prop. The dealer suggested I drop down to a 15 pitch to bring the RPMs up to the recommended range. I picked up the new prop from the dealer yesterday and hope to get it installed in the next few days.

I'm curious to hear what prop others with the same engine are using.

are you running the Yamaha reliance series SDS prop? Mine came with the SDS Stainless 15 pitch, I can hit 6K @ 38-39 mph light load.

My dealer uses PowerTech REL3 Series Props on the Yamaha. Looks like my 16 pitch is hitting just about the same speed as you are, but not getting the revs at WOT. I'll let you know what happens when I put the 15 pitch prop on! If it gives me the same performance you're getting I'll be happy. I'm not trying to get more speed, just looking to get the revs up where they should be.

I been struggling with my prop as well, except the opposite direction. I had to go up in pitch to reduce my WOT revs.
I think your new prop is going to dial you in perfect.
I have a merc on my boat and found my analog tach to be off quite a bit at the higher rpms.
Simply put, you can't trust an analog tack when dialing in max rpms and a prop.

Im jealous, I swapped props and doubled my speed....you guys are double my double, so it's like quadrupled from mine a month ago

My shit is so squirrely now at wot, i gotta fix steering this winter


ETA....I have a small old 2 stroke so it is apples to oranges up in here

15 pitch is very popular on 150 Yamaha's on these type of boats.

The Mercury Enertia is a great prop.

My Bennington has a Reliance 15 pitch prop, and it's perfect--40 mph and 6000 rpms. That's 6% slip. When I picked my boat up, it had a 14M Yamaha prop, and it was 4 mph short and hitting the rev limiter @ 6300 rpms. He had the 14M in stock and was trying to save a little $ by not ordering in a Reliance. The Reliance was built for that motor specifically, and it's comparable to Mercury's Enertia. But at $715 list price, they are pricey.

6% slip on a pontoon is worth the price of that prop! IMO

Prop slip isn't always correct. Props can vary on pitch. So unless you know the prop is pitched perfect numbers can look better than they are.

Case in point my Rebel 17 on a G2 150 with 2.17 gears, 5600 rpms at 43 WOT shows a -4 slip.

Rebel props are known to run heavy on pitch. A 17 Rebel acts like an 18 or possibly 19 pitch in other makes of props.

An 18 pitch with the same RPMS and Speed is 2 percent slip. A 19 is 7 slip.

So I'm getting very good numbers either way.

I made the prop switch yesterday evening. With the new 15 pitch, my RPM's went from about 5500 to between 5925 and 5995 at WOT. Perfect!

Top speed seems to have actually increased perhaps 3/4 of an MPH, but I was more concerned about running at the correct RPM's than I was affecting the speed. Mission Accomplished!

Oh, and it was a great evening for a test run.