9.9 2003 merc upgrade to 15hp

MFG197

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My father has this motor, since he bought it he replaced the carb with a 15hp model. is that all you have to do to get 15hp or are there other items like exhaust tube or reed valve changes. We definately saw a performance improvment, the boat actually planes with us in it.
 

WillyBWright

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Re: 9.9 2003 merc upgrade to 15hp

Horsepower is changed on like-displacement motors by changing the throat size of the carburetor, exhaust tuning, timing, porting. Anything from one to all of the above. By changing only one, you might cause an imbalance that could seriously damage the motor.<br /><br />Another extremely important thing to consider is legal liability. If the boat that motor is on is only rated for 10Hp, you could be opening yourself up to a whole lot of litigation should an accident occur. If it is found that the rated horsepower has been tampered with, you will automatically be held fully accountable whether the accident was your fault or not. The theory is that if you have more power than you are allowed, you have put yourself in the situation wheras if it were as advertised you might very well have not been in a position to be in that spot at that time. You also automatically remove the manufacturer from any and all liability. Period! That's far more of a factor in my opinion than the potential damage you could do to that motor.<br /><br />By the way...such a modification voids any and all warranties, expressed or implied.
 

MFG197

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Re: 9.9 2003 merc upgrade to 15hp

ok thanks for the legalese.<br /><br />the boat is not overpowered. the dealer said the only difference is the carb. they ordered it for us. there are hundreds of modified outboards on the lake.
 

WillyBWright

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Re: 9.9 2003 merc upgrade to 15hp

Whoop de freaking doo. I'd never do business with a dealer that would intentionally tamper with any outboard that way. They place themselves and their customers in legal peril for the sake of a quick buck. That's just plain stupid. Nobody's motor is worth that. They could lose their franchise over something like that as well. Just plain stupid!
 

Hooty

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Re: 9.9 2003 merc upgrade to 15hp

The 9.9 is already up close to 15hp. The engine was built and labeled to comply with some lake restrictions banning anything over 10hp. <br />Your dealer is correct, the larger carburetor will give the engine some boost on the top end. <br />Don't sweat the chicken littles.<br /><br />c/6<br />Hooty
 

MFG197

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Re: 9.9 2003 merc upgrade to 15hp

Thanks for the reply Hooty, all we wanted was for the boat to plane, it only goes 13 mph (with the seas), but I guess that could get me into trouble anyway putting me in a spot I shouldn't have been in...not to mention my 21.5' Sea Ray does 50mph. I should probably de-tune that and add a 2bbl to be a little safer and less likely to get sued for something...
 

mellowyellow

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Re: 9.9 2003 merc upgrade to 15hp

u guys r missing willy's point here...<br />let's say you sell this motor to a buddy in a few<br />years and he put's it on a boat that is only rated<br />for 10hp, he is stupid and runs over a jet-skiier<br />and they find out the motor was modified by you.<br />he says; "I didn't know" to cover his rump...<br />longshot 4 sure, but a pro. would never put<br />themself in that position of liability.<br />u r not being unsafe, but feces occurs.<br />anyways, am sure you are fine with the extra<br />ponies, it's a sue-happy world is all ;) <br />and hooty... chicken little? good one, LOL
 

Hooty

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Re: 9.9 2003 merc upgrade to 15hp

Hey MY,<br />Your and Willy's argument is like saying the Chevy dealership shouldn't sell you a performance package for your new car because it'll make it go faster then the speed limit.<br /><br />c/6<br />Hooty
 

mellowyellow

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Re: 9.9 2003 merc upgrade to 15hp

but cars don't have max hp. ratings Hooty...<br />as I said, I think he'll be fine with a whopping<br />5hp more, just trying to make a point to CYA is<br />all. folks need to understand liability issues<br />that they may not know. I would not hesitate to<br />change the carb myself in this sit. if I sold the<br />motor to someone, I would also make them sign<br />a statement saying they know the motor has more<br />than 9.9hp it said on the cover.
 

WillyBWright

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Re: 9.9 2003 merc upgrade to 15hp

Apples and Oranges, Hootey!<br /><br />It all boils down to character. Let's say that the powerhead roaches because of the different carb. Do you think the dealer is going to tell the manufacturer that they sold the owner a bigger carb? Heck no! This has been a problem for decades and it costs manufacturers money. Lots of it. Maybe not specifically with this motor, but in general. There are dealers that buy smaller Hp motors and "upgrade" them to larger ones and sell them for more money or offer increased horsepower on the sly to close a deal. These are the ones that will lose their franchise eventually because the motors fail at a much higher rate than stock motors and that shows up.<br /><br />Every year, dealers get a list of parts they ordered over the year to help them decide what to stock over the next year. The manufacturers generate similar lists for themselves, but for different reasons. Say a dealer orders 25 9.9Hp outboard motors to sell for the year. Then it shows up that they ordered 25 15Hp carbs. This shows up, trust me. Certain items are flagged in their computer systems, especially when the quantity is suspect.<br /><br />These dealers also tend to be the ones that will pad insurance estimates and pocket the profits. They'll quote OEM parts and prices, then put cheap aftermarket parts in instead. Or repair a skeg where they quote a new gear housing. These dealers are stealing from the hands that feed them. If they're willing to screw the insurance company...if they're willing to screw the manufacturer...who else are they willing to screw?<br /><br />YOU!<br /><br />To mellowyellow...does your document also apply to the other boaters out there that see 9.9 on the hood of a 15Hp? They're the ones that are going to sue you, not the guy with the modified motor.
 

WillyBWright

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Re: 9.9 2003 merc upgrade to 15hp

Okay. I know my position isn't going to make me Mr. Popular. That's not why I'm here. I'm here to post based on my experience and I know of dealers that have lost their franchises and lost big bucks in lawsuits because of things like this. At the very least, the Platinum dealers lose that status. Not to mention the injuries that can and do result.<br /><br />I know 5Hp sounds like diddly squat, but in this case it's very significant. If you try to squeeze 5Hp more out of a 200Hp, that'll net you another mph, two if you're lucky. But like it was stated in a prior posting, 5Hp more out of a 9.9 will likely mean the difference between slugging thru the water at less than 15mph and planing it off to 25mph or more. THAT's significant.<br /><br />Let's look at stopping distance. If you're not planing, you can come to a complete stop in well under 10 yards. Once you're on plane, it'll take at least 10 yards to come off plane, then another under 10 yards to come to a stop. THAT's significant.<br /><br />Let's face it, by giving some little 14' aluminum rowboat the ability to plane, you've completely changed the handling characteristics of the boat. THAT's significant.<br /><br />So while it might not seem like much, boosting that motor by a seemingly insignificant 5Hp is far more significant than if you do it to a much larger motor. In fact, with this specific model the result is the most profound of all models because of the planing factor. That's my opinion and my experience. Happy New Year to all!
 

MFG197

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Re: 9.9 2003 merc upgrade to 15hp

Unlike the rest of this Springarian society my father and I are not interested in what other people do. What they do is on them, not me. How dealers lose "status" or whatever. ]<br /><br />If someone puts a 15hp motor on a 10 hp rated boat that is wrong, and we would never do that.<br /> <br />People modify all kinds of engines from lawn tractors to big blocks. His boat is not some little rowboat it is a 15'sylvan that is rated at 40hp. Adding 5 hp to plane the boat is not going to kill anyone or cause him to lose his house. <br /><br />If I posted in the I/O section that I added a new carb to my 350 Merc to get 280 hp everyone would say Cool!
 

WillyBWright

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Re: 9.9 2003 merc upgrade to 15hp

Sorry, I get to Pontificating when it comes to safe boating. I was talking to too many people about too many things. My answer to your original question is "I don't know if your motor would need more than a 15Hp carb to make it a true 15Hp, but..."<br /><br />Fact is, boating is the only industry that I can think of that has Maximum Horsepower Ratings, and those laws don't even apply to boats over 20 ft. If you want to know how much power I can squeeze out of a big block chevy, I say "How much do you want to spend?" I've worked on boats with excess of 1,000Hp capable of over 100mph. But that doesn't count here. We're talking about Grandpa's fishing boat. COOL! Americana on water! I Love it.<br /><br />All I can ask is that if any warranty issues come up that you inform the dealership of the modification. Changing the decals on the hood would be a good idea. If you ever sell it, put the original carb back on, include the 15Hp carb if you wish...uninstalled...and make sure you explain exactly what it is. The latter suggestions are for down the road. It'll probably end-up on another boat sometime and it should always be appropriately represented.<br /><br />Just one more little point and I'll shut-the-flock-up. If you happen to be on one of those lakes (you're probably not) that restricts horsepower to under 10Hp, a planing 15' Sylvan with two adults and a kid pretty much HAS to be a tad more than 10Hp, doncha think? Major league Red Flag for the wardens!<br /><br />Good Fishin'. Catch me some. I prefer bullheads. Appropriate, eh?
 

MFG197

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Re: 9.9 2003 merc upgrade to 15hp

Willie, that seems logical and well put. I just get annoyed when people are afraid to live because of the fear of lawsuits. i do not however, condone stupidity. eg. overpowering a boat. He bought the 9.9 for this boat becuause he needed a long shaft and got a good deal for his old one (a 1990) which he sold. putting it on the boat he realizes that it won't plane the boat, adding the 15 carb kept this from being a costly mistake. I agree that the next owner (it will probably be his until he cant use it anymore...then maybe be mine... or something...) I do agree that the old carb should be put on if sold to another person...and then give them the 15 carb and let them make the choice.
 
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Re: 9.9 2003 merc upgrade to 15hp

I suppose the same argument could be used if you used less HP than your boat is rated for. You might be in a different spot than if you'd had the rated HP.<br /><br />Man. Have the attorneys got us screwed up or what????<br /><br />Personally I don't live my life worried all the time about possible litigation. I try to be responsible and keep safety in mind. It's not like the guy was asking if it would be OK to put at 75 HP motor on a boat rated for 10 HP.<br /><br />wile e
 

KCLOST

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Re: 9.9 2003 merc upgrade to 15hp

This is an interesting topic, as I know of several guide services that run fiberglass john boats on a well know trout river in Arkansas, that do exactly what WWYC has done. They run their motors with a 9.9 hp sticker on them, when the carb really turns the engine into a 15 or higher. Even though they risk a violation of some kind with the parks service and probably the Dept. of Revenue. <br /><br />Anyway, they have been doing it for over 20 years, and I've never heard of a problem... Kind of funny actually. IMO, experience is the most important factor when boating. More power can help you in more situations than hurt you. IF, and only if you are a careful, and knowledgeable boater... my two cents
 
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