Motor Up Grade

[Keith Poole]

I have a 2004 Starcraft 200 20 Foot Pontoon rated for a 60 hp It has a Mercury 60 Bigfoot 2 Stroke on it now I want to put a Mercury 115 Four Stroke on it Do I need to do any transom up Grades or will this boat safely handle it Keith

 

[ahicks]

There's a plate on that boat somewhere, that will give you the max hp rating. Unless you really know what you're doing, I'd suggest you heed what it says. All that aside, your 20 footer is really going to notice the extra weight of the bigger engine (NADA should be close, shows 239 vs. 357). You can expect the back of it to float noticeably lower. in the water...

 

[glust]

You run the risk of setting yourself up for a liability issue of you go past the HP limit of your Hull Identification plate or HID. I had an insurance agent tell me I might not be covered in an accident if I intentionally go past the safe limits of the craft.

 

[Merc40hp]

I upgraded an older 40 hp 4 stroke to a 90 hp Optimax with no issues on my 18' Tracker pontoon, (my insurer, progressive had no issues with it and didn't increase my deductible or raise my policy rate). Remember your talking about doubling the hp and adding additional weight, both of which puts more stress on the transom. You should do the same as I, and look everything over well, ensuring all welds are solid with no cracking or corrosion. I have no regrets with my upgrade, the pontoon performs better, goes fastener, uses less fuel cruising and is more reliable than before. About every six months I pull it from the water and inspect everything, logs, transom welds, etc... if you have kids and plan to pull skiers and or towable's, you will not be disappointed with the upgrade.

 

[HotTommy]

You'd be wise to consult a marine engineer / mechanic with lots of experience to look at your specific boat, rather than ask a bunch of strangers with little knowledge of your particular boat for advice. A bigger, heavier engine will affect the transom (mounting plate), the engine pod, the pod's connection to the boat and the boat's behavior underway. .... You're not the first (nor last) to ask advice here about this. It usually comes down to this. It's your boat, your life and your money. It's up to you to decide how much risk you're willing to take for the reward.

 

[Scott Danforth]

your boat is rated for 60hp if its a classic or 75hp if its the fishing boat model http://www.starcraftmarine.com/sites/starcraftmarine.com/files/catalogs/2004-Starcraft-Catalog.pdf

so your boat is rated for 60hp or 75 depending on the model

bolting a 115hp on it will not only rip the pod off the back, however your motor will most likely be lost when the pod gets ripped off the boat when your under throttle

 

[ahicks]

Without denying it might be possible, try as I might, I can't remember hearing or reading about somebody that's lost an engine pod completely in my 40 years plus boating experience. Close as I can get is a 40 horse that tore out of a completely rotten transom that anyone with common sense would have replace 10 years prior to that happening...

 

[Merc40hp]

No Title

I agree with ahicks, I have never heard of a catastrophic pod separation resulting in the lose of the engine, etc.. Having lived around saltwater all my life, I have seen many pontoons suffer from extreme galvanic corrosion resulting in fasteners pulling through stringers and or brackets. (see pic) but again, with proper maintenance, inspection and adding sufficient galvanic anodes and bottom paint, pontoons are good to use in any water.

 

[NYBo]

your boat is rated for 60hp if its a classic or 75hp if its the fishing boat model http://www.starcraftmarine.com/sites/starcraftmarine.com/files/catalogs/2004-Starcraft-Catalog.pdf

so your boat is rated for 60hp or 75 depending on the model

bolting a 115hp on it will not only rip the pod off the back, however your motor will most likely be lost when the pod gets ripped off the boat when your under throttle

According to the original post, it's rated for 60.

 

[Scott Danforth]

Without denying it might be possible, try as I might, I can't remember hearing or reading about somebody that's lost an engine pod completely in my 40 years plus boating experience. Close as I can get is a 40 horse that tore out of a completely rotten transom that anyone with common sense would have replace 10 years prior to that happening...

there were o few 'toons on iboats within the last few years that lost the pods. a few were trackers where the motor pod was attached by a few cables and a bolt or two, one was a johnyrude that the motor came in hanging from the steering cable (couldnt find that one quickly)

http://forums.iboats.com/forum/gene...51576-re-transom-broke-off-suntracker-pontoon
http://forums.iboats.com/forum/gene...79637-transom-and-motor-ripped-off-of-pontoon
http://forums.iboats.com/forum/gene...s/597495-transom-broke-off-suntracker-pontoon
https://www.youtube.com/watch?v=CxH6Rxk5WWM
http://www.stltoday.com/news/local/...cle_e7095e46-e83c-57b9-bd7d-f98196693629.html

Here is one to note, going up 80% more in power, no change in speed
http://forums.iboats.com/forum/gene...-installed-a-90hp-merc-no-change-in-gps-speed

 

[ahicks]

As mentioned, I've seen transom failures resulting in engine loss. That's generally a serious lack of maintenance. I was not aware of the frequency guys with Trackers are loosing engine pods as a result of use in salt water. Thanks for that.....

Still a stretch for me to believe that an engine pod is going to automatically fall off the boat if the boat it's fastened to is over powered. Comments like this seem a bit dramatic, and your links don't provide any evidence of that potential at all.

"your motor will most likely be lost when the pod gets ripped off the boat when your under throttle"

That said, I don't endorse the practice. I'm just saying that it is possible, in many cases (not all), to reinforce a boat to the point it can handle an engine bigger than what the data plate specifies as max.in a safe manner.

Our OP wants to pull a 3 cylinder Merc and install a small 4 cylinder (the 75's, 90's and 115's all use the same block) that weighs 120lbs more. If the OP is willing to deal with the back of the boat floating much lower, the necessary reinforcements should be "do-able" with proper supervision. 115hp 4stroke Mercs are seen fairly frequently on conventional 'toons, but they are right at the upper limit, and most often seen on 24 footers with oversize (24"-26") tubes.

Noteworthy maybe as well, is that Starcraft boats are pretty well known to be as sturdy as most other boats.