Prop Question Honda 135

[TDJ2591]

Hi all.

Frequent troll, new to pontoon ownership. Bought a well-maintained 25' 2005 Crest Caribbean with a 2006 Honda 4 stroke 135hp. Love the boat. Boat came with a Piranah 15x15 composition prop with replaceable blades. At WOT speed was 25mph GPS & 5000 rpm. Wanting to increase the RPMs into the operating range of 5-6K, replaced blades with 14-3/4x13 blades. Speed INCREASED to 26mph GPS but RPM DROPPED to 4500 @ WOT. Next step would be to try 11 pitch. Want to switch to SS prop but first have to find right size. I emailed the prop manufacturer and they can't understand why the unusual speed/rpm results. Have asked their engineering department to weigh in but have not yet heard back. I asked if perhaps the 15x15 was flexing or slipping.

Anyone have experience with this boat/motor combination? What prop are you running and what are your speed/RPM results? Any thoughts on how to find the right prop? There are no nearby marine dealers and I keep the boat 2 hrs from my home.

[Bamaman]

You might find a good prop shop or Honda dealer that's experienced with pontoon boat propellers. When you buy from them, their advice is free if you buy from them. And if a prop is not right, they'll often let you swap for another prop.

Hondas are fine motors, however their dealership base is not as numerous as other manufacturers. Honda props are also a little harder to find on the retail market.

[TDJ2591]

I agree that is the best option. I would love to find a dealer who could help, but I haven't been able to find a dealer within 150 miles of me. By the way, this Honda is incredibly quiet. The water noise is louder than the outboard and you cannot even hear it at idle.

[fiddlebick]

I too have the 135 honda on my 26 foot bennington. Great motor, basically the same block, same weight as the 150 hp, but doesn't have the variable valve timing...hence only 135hp. Mine runs 25 mph wot, and I have considered the express tube kit to make it a tritoon, but I am afraid of a minimal increase in speed vs. cost of the kit...still thinkin' on that one. An extra 2 grand is a lot to throw at a boat that is already nearly ten yrs old. I will look at my prop tomorrow and let you know what it is, and best I remember, I am running around 5200 rpms at WOT.

[rancherlee]

punching in the number quick that 14.75x13 is giving you a touch of negative slip if your tach is reading right. Theoretical top speed with ZERO slip @ 4500 rpm is 25.88 mph with a 13 pitch on a 2.14 gear case. Your 15 pitch @ 5000rpm is more what I'd expect to see on a 2 log with around a 30% slip (33.18mph @ zero slip, 25mph actual)

[TDJ2591]

Rancherlee,

Thanks for the info. I mistakenly said 14-3/4" diameter. It is actually a 14.5 x 13. Does that make much difference in the calculations? Is there really such a thing as negative slip?

My biggest concern is to not do any damage to the engine by putting a strain on it by running the wrong prop.

This puzzles me.

[Bryden24shp]

Negative slip, would have the boat spinning instead of the prop. Ain't seen it happen yet. But that might be kinda cool!!!

[TDJ2591]

Fiddlebick,
Were you able to check and see what prop you are running on your Bennington?

Any other members running a Honda 135 on your toon? If so, can you share your boat/prop combination?

Thanks all!