What horsepower can your pontoon handle?

usmeagle

Seaman Apprentice
Joined
Mar 27, 2020
Messages
34
Folks my 20ft Triton Cypress Cay is somewhat underpowered for pulling my son and his friends with a Honda 40HP 4 stroke, if I wanted to upgrade how do i find out what max horsepower it would handle?
 

ahicks

Captain
Joined
Sep 16, 2013
Messages
3,957
The answer is it depends....

What you'll find is that engine power = engine weight.
That makes the first thing to consider how well the boat would handle more weight.
How well your pontoon will handle more weight is going to be mostly about the diameter of your pontoons (more diameter = more weight capacity). If the waterline now is at about the half way point when looking at the side of the 'toons toward the rear, I'd be really hesitant to put a heavier motor on the back of that boat.

If the half way point on the toon is up out of the water, then maybe it WILL handle a bigger motor.

Older boats (say pre 2000) tend to run smaller diameter pontoons (18" -20"). They were designed with 25-40 hp motors in mind. Newer boats (lets say 2010 and newer) tend to run larger 'toons (say 25" diameter).

SO, all that in mind, 1. how old is your boat and 2, do you know the diameter of the tubes? or 3. do you know about where your current waterline is on the rear of the boat?

A Honda 50 or 60 will be the same weight as your 40, but I'm not sure you're going to pick up enough performance with either of those to make a swap worthwhile.

The Honda 75 and 90 are both 150 lbs heavier than your 40. Merc and Yammie both have 75, 90, and 115's that are the same weight as the Honda 75's and 90's. Any of those motors will have significantly more power that will be very noticeable when pulling.

Last, there may be some concern regarding the strength/type of construction of the motor pod/transom. If this is an older boat with an adjustable transom height, I would not mount up anything bigger than what you have now. If it's not adjustable, I would still want a look at how the motor pod is fastened to the floor of the boat. Some use just 4 bolts to secure the engine pod to fairly light cross menbers. Something like that will need to be beefed up significantly prior to putting any of the bigger heavier motors on it. -Al
 

Starcraft5834

Lieutenant Commander
Joined
Jun 2, 2013
Messages
1,677
ive got a 2019 Starcraft 20ft toon. max hp is 125.. I opted for a 115.. it's 359lbs.. check with your manf on specs, newer 4 strokes tend to be considerably lighter than older less powered 2 stroke motors
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
What's the min-max wot rpm range factoy stated for that particular motor, what's the max wot rpm achieved as currently loaded asumming the boat has an installed tach ? The actual prop powering said motor could be way over propped for that application. Will need to bump max wot rpm higher with less prop pitches. Won't have a speed demon, but will work much better than of right now, that's if don't want to go for a higher HP motor any time soon...

Happy Boating
 

ahicks

Captain
Joined
Sep 16, 2013
Messages
3,957
40 hp Merc 2 stroke, about 190.
40-50 hp Honda 4 stroke, about 250.

All else being equal, 4 strokes are heavier, but not THAT much heavier (double). Unless you're increasing the hp.

Noteworthy, is that most 4 strokes will have TnT. Many (most?) older 2 strokes did not.
 

jebby

Petty Officer 2nd Class
Joined
Feb 23, 2009
Messages
185
10hp Johnson sea horse 2 stroke 68 lbs
15hp merc 4 stroke (same block as 10 hp) 126 lbs.

I used to put them in the truck and the boat upside down on the pop up camper. had to sling them regularly. I know how much that extra weight sucked
 

clemsonfor

Lieutenant Junior Grade
Joined
Sep 19, 2005
Messages
1,011
The short correct legal answer is look at the USCG capacity plate for your boat. It will list max cargo/passenger weight as well as the MAX HP of the boat as well.
Some of this data can be found on certain websites or even manufacturer data if there still around or they existed at all during the digital age.

Sure you can put larger, but legal issues could arise down the road. Just use your mind to think of these.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,590
Got a Lowes 245 rated for 115HP with 150Hp ,Insurance said nothing on overating
 

ahicks

Captain
Joined
Sep 16, 2013
Messages
3,957
My ins. co. does. They even want to know how fast it will go.

When it comes to overpowered boats, I always wonder what the company will do in the case of a claim of any consequence. Will they cover you, or try and squirm out claiming it's overpowered - even though they've accepted your payments for the last several years? Grey area from my perspective. So typical for insurance companies to pull on you when you believe you're covered.
 

usmeagle

Seaman Apprentice
Joined
Mar 27, 2020
Messages
34
Yes I have looked at the back of the boat for a capacity plate and i have found nothing other than a serial number. Where else could it be?
thanks for all the replies
 

usmeagle

Seaman Apprentice
Joined
Mar 27, 2020
Messages
34
I see the sticker now unfortunately I can’t read it, any other recommendations?
 

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usmeagle

Seaman Apprentice
Joined
Mar 27, 2020
Messages
34
Thank you so much.
either need a more powerful motor or going to get a new toon next summer.
 

ahicks

Captain
Joined
Sep 16, 2013
Messages
3,957
When shopping, I generally watch what engine comes with the deal closely. Changing it, re-powering after the fact, way more expensive. I've passed on many right boat wrong motor (and vice versa) deals.
 
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