Hull horsepower rating?

[Gman 82 aquasport]

I have a 1982 aquasport C/C rated for 185 horsepower. Would it be a real problem to put a 200 HP motor on this size boat? Is the 15 extra horsepower and the added 40-50 pounds of weight going to cause problems?..

 

[JimS123]

Re: Hull horsepower rating?

Yes, its a really really big problem. Do a search and you'll find that 84,000 others have asked the same question and were all advised by the experts not to do it.

 

[wifisher]

Re: Hull horsepower rating?

The same topic has been done a LOT of times. Do a search and you will see plenty of answers. Just remember that what you are asking to do IS illegal, and could get you a fine if it were inspected. And could cause your insurance co to be upset with you. Other than that, it is up to you. Roll the dice if you want.

 

[1979checkmate]

Re: Hull horsepower rating?

well... i would do it. That sure as heck doesnt mean it is a smart thing to do, but some 175 decals would get er done. Here is how i look at it. if someone had a 175 outboard, but has it modded (various things can be done) to easily achieve 200 hp.. It is still a "175" and i have never heard of anyone getting in trouble for a modded powerhead.

 

[Brewman61]

Re: Hull horsepower rating?

It's something that you could do on your own, but would be foolish for someone to advise you on. The people saying to go ahead don't have to suffer any consequences- you do. Will disaster ensue simply because your boat is 15 hp over? Who can say? Is it possible?
Yes. Could there be consequences with the law or possible future sale? Yes. Will there be? Impossible to say.

 

[Gman 82 aquasport]

Re: Hull horsepower rating?

Thanks for the info, I'm waiting on a call back first of the week from my insurance company with their take on it. So many people around here are running with larger motors that it gets a little muddy trying to figure out if it causes problems or not, no one here says anything about the legal ramifications of being overpowered... So it will be taken under advisement as to will this 200 hp go on my boat....if not I will find a swap for a 150 or 175 hp local....

 

[Bob_VT]

Re: Hull horsepower rating?

If you exceed the USCG rating and should have an accident....you can be held at fault and lawyer's will have a great time in stripping your estate. Overpowering a hull is reserved for racing and that is why we do not drive NASCAR contender's on the street.

 

[dazk14]

Re: Hull horsepower rating?

You'll get a ton of opinions. You've gotten a few solid point of views above. You'll also get the individuals that are outraged that you would even consider it. Mind you they are replying on their crackberries while driving 75mph on the highway.

Normally, there would be a negligible difference from a 185 and 200 in both power and weight. I could set up a 185 to easily outperform a typical installed 200. It's not uncommon for the lower HP to have more low end torque. You would want to de-sticker the 200 to avoid nit-picking and leave the throttle cable a couple turns light. Yes 1.5 more mph max on top is nit-picking.

I'm taking the time here to reply, because good used outboards can be tough to find and new is simply out of reach for most people.

If you have another reliable outboard lined up, then sure, make the swap. If you were looking new, then of course, get the correct motor.

Now, on the negative side... Your boat was made at a time when outboards were switching over to prop rated HP, so I can't say with certainty that Aquasport had that dialed in.
The other concern I have when putting near max HP on ANY older boat is inner core transom condition. I have drilled into 2 year old transoms that poured out water!

For whatever reason, I don't receive notifications from this board, so I may be 1 and done on this one.

Good luck!

 

[dazk14]

Re: Hull horsepower rating?

Just to add an interesting point to the - close to rating - HP overpowering topic.

Any boat made before 1980 using a post 1980 max hp motor has over-power it's vessel - period.

I think most mechanics would agree that a modern 115HP is roughly equivalent to a mid-70" OMC 135/140HP. Yet, boats were (and are) routinely fitted with modern era motors.

Why the Lawyers haven't picked up on this is surprising...

 

[Gman 82 aquasport]

Re: Hull horsepower rating?

Thanks dazk14 for the info and inlightment..I have a couple of feelers out for a motor but will do nothing until I hear back from my insurance people on their take...If I do use this motor I will repaint it and apply new (175) stickers.Like you said not everyone can drop 4-5K on a used motor or 12K on a new one, most of us live in a real world with other concerns and obligations...I will leave this one alone now until i get info from my carrier..

 

[dazk14]

Re: Hull horsepower rating?

Without knowing the model year of the motor... If you would like to convert it to a 185 or lower...

Retard the timing 2 or 3 degrees and 2 or 3 turns loose on the throttle cable would drop the hp ~15 or so.

Many mechanics(including top rebuilders) feel that with the crappy fuels these day (that keep getting worse), retarding the timing a couple degrees(or more) is a must on many motors.

You may find a used cowl to match your newly de-rated outboard.

 

[JimS123]

Re: Hull horsepower rating?

If I do use this motor I will repaint it and apply new (175) stickers..............not everyone can drop 4-5K on a used motor or 12K on a new one, most of us live in a real world with other concerns and obligations....

That's Oh so true. Boating is just too expensive if we have to do eveything right. In the real world it's just so common these days to abandon common sense and just simply do what is the cheapest way out. I do fraudulent things all the time and I've never been caught. My concerns, priorities and obligations are saving money.

 

[dazk14]

Re: Hull horsepower rating?

Just an info update...I would suggest, it would be prudent to triple-check the attached statements.

I spoke to a few of my customers that run oversized motors and they said they had no trouble getting insurance. One indicated the price was a bit higher due to the added speed (per his agent).

All indicated that the Coast Guard doesn't require HP ratings over 20' and do not enforce hp capacities as many think, although - apparently - each individual state has their own regulations. One is a CG Cadet, and he indicated that if the weight of the occupants and motor appear to be overloading the boat for the existing conditions, they would require them to return to port.

I spoke to an associate at a neighborhood shop with a Dyno and he indicated - after chuckling - that his shop could and would de-tune a 200 to produce 185max and would sign off on the Modification and provide a complete printout of the as-built product - although it would be a first.

Good Luck!

 

[Gman 82 aquasport]

Re: Hull horsepower rating?

My insurance co. got back to me from their underwriters and said no problem what so ever.. they told me that they don't usually have a problem writing coverage as long as you don't go more than 15% over, then it's usually just higher premiums unless you way overpower... So it looks like I will use my 200 and adjust the throttle cable and adjust the timing a little.... Thanks dazk14 for the extra info..I had checked with 3 or 4 shops near here and all said they would put it on no problems...

 

[JimS123]

Re: Hull horsepower rating?

Shouldn't be a problem. The insurance company agrees, the authorities don't care, so you're good to go. If you have an accident, just tell them you detuned it a little based on internet forum suggestions.

All you have to hope is that the guy you tangle with doesn't have a lawyer that finds out you exceeded the capacity rating. I know if it were me that would be the first thing I'd check, and if that was the case I'd own your boat, car, house and firstborn.

 

[5150abf]

Re: Hull horsepower rating?

And be aware that normally when a transom fails they don't fail alittle, the go all at once and normally at full throttle, ask yourself if you want to deal with a 200hp engine at full throttle attached to 2 cables in a rapidly sinking boat.

 

[Bob_VT]

Re: Hull horsepower rating?

And be aware that normally when a transom fails they don't fail alittle, the go all at once and normally at full throttle, ask yourself if you want to deal with a 200hp engine at full throttle attached to 2 cables in a rapidly sinking boat.

I had a friend who lost a 200 mounted on a jack plate to the bottom of lake Champlain...... When the motor went ....it managed to take EVERYTHING with it including the helm! His boat was rated for it..... and it just went.

 

[emoney]

Re: Hull horsepower rating?

To the OP, just because some folks don't give you the answer that you were hoping to
hear, doesn't mean they're handing out bad advice, nor does that make them "negative"
people. That's the risk in asking an open ended question; you may not like the answer.
I, for one, know that around here, you can and will catch heat if the USCG sticker doesn't
allow for what's actually hanging on the back, and the extra "only 45 lbs" is a whole lot
more than it sounds. In some cases, it's adding almost 10% to the overall weight, which
means you will probably need to compensate with weight distribution in the bow.

Doesn't mean it's not a "great deal", and if it truly is, then buy it, and then trade someone
that has a newer, lower hp OB and everybody wins!

 

[Gman 82 aquasport]

Re: Hull horsepower rating?

Getting ready to make a deal to trade my 200 for a 150.... keeps everyone nice and happy and keeps the USCG and insurance people of my a%%...insurance underwriter informed me Friday that they would cover the boat overpowered but could not garuantee tha tin case of incident that they would pay the claim because of being overpowered.. so I found someone with same year 150 and we are planning to swap...So we can put this story to bed now..

 

[v_fourmax]

Re: Hull horsepower rating?

I would tend to say that you find a very divided line on those that say no way do not do it and those that within reason do not see where maybe bumping up just a small amount could be considered not such a big deal.

First off my understanding (correct me if I am wrong) is that the Federal Coast guard regulations do not make it or the boat "illegal" if you exceed the recommended hp rating. It is exactly that a recommended hp rating. Now there are some states where the state laws do make such modifications illegal and operating in waters within their boundaries you could be ticketed for an illegal boat.

But many states just follow the coastguards wording and just being over the hp rating is not "illegal". Now granted if you were involved in an accident that does not mean some savy lawyer will not try to make it an issue as a contributing factor. That will be a risk that you need to decide whether or not is acceptable the way you operate your boat.

Sometimes a person may consider a slight bump in power and "how fast it will go" will not be the main purpose behind the proposed bump.

I have a 17' tin bass rig that is rated for 75 hp. I currently am running a Mercury 50 hp two stroke and have an interest in repowering to a 4 stroke motor. Researching the upgrade to a 75 hp an optimax 75 hp 2 stroke weighs 373lbs. A 75 hp fourstroke weighs weighs 397 lbs. Now as far as being "legal" either of these motors would be fine.

Doing a little more research a 90 hp 4 stroke weighs the exact same as the 75 hp 4 stroke. As far as performance the the 75 optimax would definately outperform the the 75 hp 4 stroke and would probably be pretty close on par to the 90 hp 4 stroke.

Now actually since I am wanting the 4 stroke rather than the two stroke opti then it would appear that just total top end speed is not my primary concern. I am intersted in the smooth idling trolling aspects, quiet operation and reasonable fuel consumption along with not needing to worry about keeping the two stroke oil topped off.

Now also I have upgraded to a 24 volt trolling motor so we have the extra weight of another battery, am considering adding a couple of power poles so the boat has a bit of added weight as well. So considering that I am leaning very heavily into going with the 90 fourstroke over the 75 fourstroke. I like running to my fishing spots when conditions are good cruising in the mid to upper 30's range. I feel that the 90 will cruise those speeds at a little less of a throttle setting and be working a bit less and make the boat more efficent to operate than what the 75 4 stroke would do to maintain the same performance. Also the 90 with a normal weight load will pop up on plane better and quicker as well.

So in this particuliar application I really do not feel that adding 15 hp over the max hp rating is making for a package that is overpowered at all from its intended performance. The 90 hp adds NO weight above the rated 75 hp 4 stroke. As far as speed is concerned the 90 4 stroke will probably at best be equivelant to what the 75 hp optimax 2 stroke would deliver and that is also within the rated specifications.

So am I saying that it is okay for anyone to do this? Actually each person has to weigh for themselves what works the best. In my state it is not illegal to operate a boat just because the motor exceeds the max hp rating, if it was I would probably reconsider just on that fact alone. I have had my go fast bass boats in the past and speed above a level I like to cruise at is of little to no interest as about 40 mph is pretty much the fastest I want to go anymore.

What I find to be of more importance is to get on plane quickly, be able to run the speeds I want to run efficently in the sweet spot for fuel economy and with less strain on the engine for longevity. So personally I am one that when it comes to a person making a decision whether to slightly overpower what the max hp rating says then perhaps it pays to pay attention more to what the person has for reasons for doing so instead of just telling that person how wrong they are.

I would be the first to agree that an older boat that has had its rating designated with powerhead ratings should really be careful and not exceed those rating with a newer rated at the prop motor because even then they are exceeding what the boat was actually rated for. I would also tend to agree that the weight of whatever outboard they are considering going to should be in the same weight range of what the engines the boat was rated for and if heavier like in the case of a newer 4 stroke care should be observed.

There are a lot of bass rigs out there that within their rated horsepower will run 90+ miles per hour and anyone with a pocket full of cash even if they have never sat behind the wheel of a boat can go out and buy one and not have a clue as to how to safely operate such a machine. There are also plenty of those same people that will have onboard a cooler full of bud lights that such cooler gets lighter and lighter as they are out on the water and those people concern me a lot more as far as my safety than someone that is safely and soberly operating their boat that may be over max hp by 15-25 hp.

One final thought is the newer dfi and 4 stroke outboards with a scan tool the motors rpm ranges can be pulled by a tech and like a black box if an accident occurred and the motor was only being operated at say 3500rpm it would be mighty hard for a lawyer to twist that into the slightly higher hp motor contributed to the accident because of excess speed. We all have the limits that we feel comfortable with and they may differ from individual to individual.