Putting a larger engine on the boat than whats its rated for

Im contemplating upgrading my motor on my 97 skeeter 1775c Tiller. I currently have a 75hp 2 stroke and want to upgrade to a 115 or 150 4 stroke. What are the ramifications of having a larger engine than what its rated for? Thanks in advance

You will be told it’s against the law to exceed the coast guard rating. That said when I wanted to go bigger on my Skeeter I couldn’t find anybody who cared. The DNR I talked to sure didn’t. I’ve never been checked on the water on what size my boat was rated for.

What you will find is NO DEALER will hang it. They are afraid of the liability. So, if you buy the motor and hang it yourself you will be OK. That said…..if you are ever involved in a on water accident the opposing attorney will fillet you if they get the chance.

IMO you are looking for trouble if you hang a 150. Heck a 115 would fly!

I think it would be tough to insure, but that’s just an assumption.

I’d call your agent and see if it’s okay first.

I used to have a ’01 Warrior V177 (17′ tiller) with a 125 Mercury and power hydraulic steering…..that thing was an animal!!…..but it was “rated” for it.

I’ll also add, that even if it’s “okay,” repowering is ALWAYS a money losing proposition…..

You’ll never get back what you put into it…..but if it makes you happy, it can be worth it.

Fiscally, you be much better off finding an early 2000’s Warrior that has Pro Tiller steering and already rigged.

Bad idea. Insurance will use exceeding cost guard approved hp as the basis to deny claims. I would think if you had accident you would be sued for sure. I think only the coast guard enforces the rule. So if you never go on coast guard water. Leech,winni gull,whitefish chain ,cross lake chain,st croix, Mississippi millelacs perhaps you will never get checked. In any case I wouldn’t do it unless insurance guarantees coverage in writing.
Mwal

Also the problem with rating in part involves weight. A boat rated for a 75 HP 2 stroke would be over weight with a 75 HP 4 stroke as the 4 strokes are much heavier per HP. The bow of your boat might point to the sky with that bigger 4 stroke.

I think if you were to have an accident your toast.I don’t think there would be an attorny that could win that lawsuit.

I’ve seen it done lots of times. I wouldn’t suggest the 150 on it. But I bet a 115 would be fine. Meaning for functionality
Just like everyone else says. It the insurance factor that will bite you in the a$$

I know there are a lot of guys thinking…..my boat is older nothing will happen, I can go without insurance.

Few years ago there was a guy from Illinois on vacation on Kabatogama. He got towed in after slamming his boat into the rock reef. When he headed home his boat was crooked on the trailer, the hull was dented & the lower unit was strapped to the boat to keep it from falling off on the trip home. He was self insured (no insurance) his wife was bruised from being tossed out of the boat. I’ll bet it was a fun ride home.

You never know what can happen.

BTW, he never offered a thank you or to pay for the time for the 2 guys who spent 3 hours getting him loaded and safely on his way. Real class act.

I’d be real careful adding that much weight to the back of the boat. 75hp 2 stroke to 115 4 stroke is a good chunk of weight and the performance of the boat could be terrible. I’m sure you’d get more speed but at anything but full throttle it would be real hard to keep the nose down and I would imagine have a heck of a porpousing issue. Gonna be a real expensive experiment

I appreciate all the input! A lot of things I didn’t consider. I think i’m just gonna continue with my 2 stroke until I decide to upgrade. Thanks again. Happy Easter

The stress on the transom has not been mentioned at all.

I would be concerned about that issue.
Just my 2 cents

WK wrote:

Im contemplating upgrading my motor on my 97 skeeter 1775c Tiller. I currently have a 75hp 2 stroke and want to upgrade to a 115 or 150 4 stroke. What are the ramifications of having a larger engine than what its rated for?

Really a bad idea. Absolutely no way will that transom take that much additional weight and stress without bad things happening. It may not be tomorrow or next week, but use a rig long enough with the transom that overloaded and over-stressed and whatever happens won’t be good. I can easiy see stress cracks forming and letting water ingress into the transom.

Also, a rig that’s grossly overpowered like that won’t be easy to sell.

Grouse

TheFamousGrouse wrote:

<div class=”d4p-bbt-quote-title”>WK wrote:</div>
Im contemplating upgrading my motor on my 97 skeeter 1775c Tiller. I currently have a 75hp 2 stroke and want to upgrade to a 115 or 150 4 stroke. What are the ramifications of having a larger engine than what its rated for?

Really a bad idea. Absolutely no way will that transom take that much additional weight and stress without bad things happening. It may not be tomorrow or next week, but use a rig long enough with the transom that overloaded and over-stressed and whatever happens won’t be good. I can easiy see stress cracks forming and letting water ingress into the transom.

Also, a rig that’s grossly overpowered like that won’t be easy to sell.

Grouse

I’ll bet the console version of that boat allows a 115…..so the transom is probably up to par…..

Yeah the console version allows for a 150 so I guess I wasn’t concerned about the transom handling the extra weight

The weight differences are usually a wives tale since most don’t realize the differences are not extreme. I.E. the same engine classes use the same blocks, piston, and casing sizes with the only differential being larger carbs and lower units. A 2000 merc 90 weighs 359 lbs, while the 125 weighs 355. Boats transoms are tested at higher motor capacity than the rated sticker. If you’ve ever noticed a coast guard or G&P boat, they are all over rated in order to produce speed and reliability, most having 2 or 3 at the rated capacity. I have had 2 jon boats that were both outfitted with over sized motors and an after market stainless steel transom plate, an 18 ft with a 90 hp yamaha-rated for 60hp, and a 21 ft alumacraft tunnel hull with a 200hp evinrude, rated for 115hp. No transom issues, No issues ever with being checked by the G& P, licensing, or insurance/. You will have to rig it yourself, since a dealer won’t mount an over rated motor.The choice is yours, do what you want within your reason and safety factors.

The coast guard formula is the bible for now……and for what it is worth also the law. Antiquated at best…..

I have the same issues with my 690 Ranger, rated for 90hp, I went to a 90 hp 4 stroke. wishing I could have been bigger. Granted the bigger would have gave me high top speed and maybe more power for a hole shot. But I changed up props to gave me what is go for holeshot and slow trolling. If I needed a racing boat I could have bought one, I’m looking at a fishing rig, and what gets me to and from the spots. The bigger issue is are you fishing tournaments? then buy a new and bigger boat with the maxed out motor. At that rate your will be going to a warrior, as they can operate the really big tillers.

Dean Marshall wrote:

The coast guard formula is the bible for now……and for what it is worth also the law. Antiquated at best…..

Any chance The Boat Center wants to hang a 300 yami on the back of my 2060??

You know I like to go fast.

Over 20′ and you’re exempt…… seriously.

You could hang a 400hp on that boat if your heart desired