increasing horsepower

[dcamper]

i have a 2500 re san pan 25 foot pontoon, with a 115 yamaha 4-stroke. I get around 25 mph gps(27 mph on speedometer), with the boat not loaded, at top speed. I am looking to upgrade to a 150 4-stroke yamaha to get more speed when pulling tubes etc, especially when the boat has people on board. I have already changed to a SS prop at 15 pitch, which has helped alot with blowout, out of the hole take off etc. Would anyone have an educated guess as to what speed I might gain? The plate on the boat is max at 150 hp, so I cannot go over that. Just trying to weigh out if this upgrade is worth the money.

Thanks in advance for your advice!

 

[EGlideRider]

Re: increasing horsepower

2 to 3 mph.

 

[lakegeorge]

Re: increasing horsepower

Go on the web and type in Boat test you will find a few boating magazines with many pontoon boat tests, you may find yours or one very close to yours.

 

[dcamper]

Re: increasing horsepower

Thanks. Went to boat test.com. Found several boats in the same size and weight range I have using a 150 4 stroke. Most rated top speed around 35 mph, which would be a decent increase from my 24-25gps speed. Besides speed are there any other advantages or disadvantages with going from a 115 to a 150?

 

[crablegs]

Re: increasing horsepower

The 150 is a 6 cylinder instead of the 115s four cylinders, which means it uses a lot more gas and if you need to rebuild it, its got two more of a lot of things!

 

[steelespike]

Re: increasing horsepower

The 115 uses about 11.5 gph at wot,the 150 about 15.
Why a 4 stroke.Have you considered a direct injected 2 stroke like the Evinrude Etec?
Less parts,fewer less complicated service intervals,no breakin,no service for 3 years or 300 hours. 50lbs lighter.

 

[Bamaman1]

Re: increasing horsepower

New 115's vs new 150's--$3000 price difference. Since your motor is used, it's going to cost you substantially more than $3K to get 2-3 mph.
It doesn't seem worth it. Maybe you could invest in some lifting strakes to give you a better bang for your buck.

2 stroke vs. 4 stroke: I have a 115 hp 2 stroke on my pontoon. The 4 stroke just feels so much better on a pontoon boat--and is so much quieter.

 

[EGlideRider]

Re: increasing horsepower

I've had 115 2 and 4 strokes on 24 foot pontoons with my latest being a 4-stroke. If I ever own another, it will be the 2-stroke for reasons outlined by steelespike. I found that the 4-stroke is quieter at low RPM's but that advantage disappeared quickly above about 2K RPM's.

 

[dcamper]

Re: increasing horsepower

Have not thought about the etec. Will do some research. Thought I might stay with yamaha since the controls are the same. What is a typical selling / trade in price for a f 115 yamaha with 140 hours on it?

 

[EGlideRider]

Re: increasing horsepower

According to NADA, the average retail for a 2009 model is about 7 grand.

 

[dcamper]

Re: increasing horsepower

Thanks. I'm gonna keep doing my homework. Great forum!!