One decision often faced by pontoon boat owners is whether to opt for a 90 HP engine, or pay a little bit more money and choose the a more powerful 115 HP. I’ve done some research and below are some typical speeds you might expect to be able to get.

With a 115 HP engine in your pontoon boat you might expect to be able to go as fast as 25 to 31 miles per hour, depending on certain variables relating to your boat weight load, size and other adjustments. Typically, you could see a 10% speed increase versus a 90 HP engine.

But, that’s not the full story, as there will be larger variations at play, and below you can see further examples of speeds depending on different boat configurations.

  • G3 Suncatcher 22-foot V22RF with 115 HP engine and medium load could go as fast as 25 miles per hour.
  • With 11 passengers in the same boat configuration and 115 hp engine, it will go slower, at around 22 miles per hour.
  • With just one person in the G3 Suncatcher, it could reach a top speed as fast as 31 miles per hour.
  • On a standard 24-foot pontoon boat with a 115 HP engine and a medium load you could go as fast as 25 miles per hour.
  • Alternatively, a Gigantic 30-foot pontoon boat with a 115 HP engine will probably only go as fast as 15 miles per hour.

Above are some real-life examples of the types of speeds you might be able to achieve, and how fast your boat will go.

As you can see, the heaver and larger the boat, the slower it’s going to be.

Understandably you will want to know whether it’s worth the money to you, and actually how fast a 115 HP pontoon boat will go with a more powerful engine on your particular boat.

Should You Choose a 115 HP Vs a 90 HP?

Before you decide to spend money though, let me say one thing.

I have never heard anybody say that they wish they had chosen a lower horsepower engine. Never. The more common statement is that they wish they had chosen a more powerful model, such as one with 115 horsepower.

engine size

The 90 HP versus 115 HP argument has been confusing newbie pontooners for years.

Let me weigh in with some personal experience.

Always Choose the Biggest Engine Your Pontoon is Rated For

I would always choose a 115 instead of 90 and advise pontooners to always have the biggest motor that your pontoon is rated for.

I have two friends who own boats.

Jim has a Mercury 2 stroke 90 HP engine on his Starcraft V Hull 17-foot aluminum boat.

Evan has a Mariner 115 which is the same as the Mercury engine on a 17-foot Tracker hull.

Jim can go as fast as 41 miles per hour on open throttle full speed, whereas Evan can hit speeds of 45 miles per hour. So, in other words, Evan is getting a 10% advantage in speed due to having a 115-horsepower.

If you apply the same logic and percentage increase to your pontoon boat, then you might come up with differences in speed as below:

  • 21-foot pontoon boat with a 90 HP engine could hit 25 miles per hour
  • 21-foot pontoon boat with a 115 HP engine could hit 28 to 30 miles per hour

Improved Manoeuvrability

Other reasons to upgrade other than speed, is you will be able to turn a steeper and bigger propeller that will give you more of a hole shot. You are also going to be able to maneuver much better, particularly in the dock and coming up or down the ramp.

If it were me, I would pay the additional $750 dollars or however much it costs you to upgrade and choose a 115 HP over a 90 HP on your pontoon any day of the week.

It’s Not Just About the Horsepower

When you take a look at the HP versus weight, then the gear case ration between a 90 HP and 115 HP pontoon engine will be different. The 115 HP has a 2.07 ratio which lets it turn the propeller more efficiently.

Getting the most speed out of your motor isn’t just about how much horsepower you have. Many times, it will also be about how efficiently you get the horsepower into lake or river water.

For example, a 115 HP engine will send more usable torque to your propeller, and even more so if you have the correct 4 blade propeller fitted.

When talking to your boat dealer, they should be able to help you choose a 4 bladed propeller. The reason being, is that it can give you a better speed straight off the bat and will not blow out in turns. That in turn helps the 115 HP run more efficiently and could even help to improve your fuel consumption.

How to Speed Up a 115 HP Pontoon Boat

Once you have upgraded to a 115-horsepower engine, you’re going to want to know how you can get more speed out of it. You can read my speeding up tips elsewhere on Pontoonopedia, but here there are in a concise format.

  1. Trim the engine
  2. Keep the tubes clean from debris and algae
  3. Change the pontoon boat’s thrust
  4. Change the pontoon’s lift
  5. Reduce the weight load and passengers
  6. Fit lifting strakes
  7. Add a third tube to convert to a tritoon
  8. Don’t fill the gas tank up completely
  9. Distribute the weight on board evenly
  10. Under skin the pontoon boat
  11. Travel downwind

Conclusion

I have always had a 115 HP on my pontoon boat, and it does go fast. I can’t compare it to a 90 HP, as I’ve never had one on my own pontoon.

But what I will say is that the 115 HP engine I run, lifts my 22-footer up onto the lifting strakes and can go as fast as 30 miles per hour on a good day, with just me on board.

If your pontoon boat is rated for up to 115 horsepower, then definitely opt for it. I genuinely believe you will be happier and won’t have that air of regret in the future when you look at that 90 HP and say to yourself “I wish I had upgraded”.

Once you have it on board, you will soon find out how fast a 115 HP pontoon boat will go!