Mercury - 40 to 50 HP by changing the carb

[laybackman]

I own a 1998 Force 40 HP engine. It is manufactured by Mercury. All parts are Quicksilver brand. Original carb number is <br />1300-854446. The 50HP carb number is 1300-854447<br />There are no other STOCK differences between the 40HP model and the 50HP model that I can find in their factory manual that I have or their factory parts list. Are there any STOCK changes that are not listed in their factory manual or parts list? And yes it does go faster...about 4-5 knots. The only other easy thing I think could be done is to change the prop to get a larger exhaust port, or change the prop dia. or pitch which I shall address in my next post. Thank in advance for any useful feedback!

 

[Mercury140-I6]

Re: Mercury - 40 to 50 HP by changing the carb

Hello:<br /><br />Being that you have a Force motor, (Even if it was manufactured by Mercury), you would get a better responce in the Force/Crysler portion of this board.<br /><br />Craig

 

[laybackman]

Re: Mercury - 40 to 50 HP by changing the carb

Originally posted by Mercury140-I6:<br /> Hello:<br /><br />Being that you have a Force motor, (Even if it was manufactured by Mercury), you would get a better responce in the Force/Crysler portion of this board.<br /><br />Craig

If all the parts a mercury and not chrysler and the design is by Mercury don't you think it should be here or does Chrysler also own Mercury?

 

[laybackman]

Re: Mercury - 40 to 50 HP by changing the carb

How come the Mercury name is on an engine that is not made by them?? I am thorougly confused!

 

[laybackman]

Re: Mercury - 40 to 50 HP by changing the carb

topic moved to force/chrysler

 

[2springers26]

Re: Mercury - 40 to 50 HP by changing the carb

Mercury.. Ign parts..& gearcase.... force block & internals....

 

[phatmanmike]

Re: Mercury - 40 to 50 HP by changing the carb

but to answer your questions, it is more than just swapping a carb... if it were that simple, that would mean that the lower 40hp moptor would either be running lean, or the 50hp would be running rich.... it has more to do with the exhaust, but keep in mind... these motors only have to make within 10% of their advertised hp ratings, so that 50hp that your trying to reach could really only be 45hp and that 40hp motor could really put out 44hp.... you wont gain much by swapping a carb... its been tried a thousand times by a thousand people<br /><br />sorry<br /><br />m ikey

 

[laybackman]

Re: Mercury - 40 to 50 HP by changing the carb

If your fuel to air ratio is correct than you DO NOT run lean or rich. You only run lean when your fuel to air ratio is too low, and rich when your fuel to air ratio is too high. When you introduce MORE air/fuel mix into the cylinder you get a bigger "bang" per plug firing hence more horsepower. Horsepower gain is all about getting as much fuel into the cylinder at once as possible that is the right ratio, or everybody in racing is doing it wrong, don't you think?

 

[laybackman]

Re: Mercury - 40 to 50 HP by changing the carb

Another way to increase HP is to alter the exhaust system. Solas Amidas on this site sells props that are supposed to provide more HP because of a larger diameter exhaust porting in their props. It's all about burning the maximum amount of fuel and exhausting the greatest amount after combustion.

 

[phatmanmike]

Re: Mercury - 40 to 50 HP by changing the carb

the reason i wrote about it running rich or lean, is usually the guys in the evinrude forum always talk about just bolting on a bigger carb and off they go, and you simply cannot do that. i understand the reasons and drawbacks of doing this, but i figured the one asking did not.

 

[laybackman]

Re: Mercury - 40 to 50 HP by changing the carb

That's because Evinrude detunes many of their engines. If you take an old Evinrude 9HP outboard and compare it to an Evinrude 15HP the only difference seems to be the carb.<br /><br />Car manufacturers did the same thing to meet emmission requirements. Smaller amount of fuel into a given engine combined with a restricted exhaust equals less horse power and cleaner emmissions simply because you are burning less fuel. Anyone who plays with cars knows that cheap horse power can be had by changing the mass air flow sensor in the fuel injection systems of the newer cars,with one that is larger or simply remove the restricter they install at the factory. Next biger injectors. Than you erase the brains presets. Next you throw away the entire exhaust system from the manifolds back and install a header(s) and a free flowing exhaust to include a free flowing cat comverter and you just bought 50HP for less than a thousand dollars and didn't touch anything major. To finish the process you start up the car and take it for a ride and it will adjust to all the changes you made since the presets have been erased it "relearns" how to manage the fuel again.

 

[merc_500]

Re: Mercury - 40 to 50 HP by changing the carb

changing a carb is not going to give ur 40HP the power of a 50HP. UNLESS, you change and jet the carb properly, and do some more extensive modifying.

 

[laybackman]

Re: Mercury - 40 to 50 HP by changing the carb

merc_500: Consider your reply and then please read the first item in this thread. Apparently you didn't. The 50hp carb HAS a larger jet already AND it's throat IS bigger to match that larger jet so the fuel/air mix is correct but delivers more volume than the 40hp carb. By the way if you jet the 40hp carb and remain at the same altitude it will run fine but rich until the leg goes in the water and when you put the motor in gear it will bog because jetting only gets you more fuel but not more air. Is that understandable to you??

 

[Mercury140-I6]

Re: Mercury - 40 to 50 HP by changing the carb

Laybackman, first you ask a question about a Force motor on a Mercury board, then anytime someone says something that says it won't work, you bash them. If you are so sure that bolting a 50 carb on a 40 block, then do it and stop talking about doing it. I mean really, how badly can you screw up a Force/Chrysler engine anyway?

 

[ledgefinder]

Re: Mercury - 40 to 50 HP by changing the carb

Actually, there are motors that are different in only the carb venturi size. Two examples are the early 1980s Merc 18/25hp twin, and the OMC 9.9/15hp twins from 1975-1981(? not sure of year). <br /><br />Laybackman, if you go to one of the online Merc parts diagrams (www.dolleroffshore.com is one), you can check what the differences are in parts between various motors.

 

[laybackman]

Re: Mercury - 40 to 50 HP by changing the carb

Everybody take a nice deep breath, OK? <br /><br />1.)I asked a question in my first post but NOBODY addressed it. I'll repeat it again: "Are there any STOCK changes that are not listed in their factory manual or parts list?" That's two times. Nobody addressed this question, but had plenty to say.<br />2.)I HAVE the factory manual and the factory parts list. I did do the carb upgrade. It works fine and I get more speed out of it. Nobody saw that in my question.<br /><br />My english couldn't get any plainer.<br /><br />These forums work only when the answers address the specific question asked. Look at this particular thread as an example. Nobody thus far has addressed my only question: "Are there any STOCK changes that are not listed in their factory manual or parts list?" That's three times.<br /><br />I did not ask if it would work or not.I know it does. I needed to know: "Are there any STOCK changes that are not listed in their factory manual or parts list?" That's four times. <br /><br />If you have an answer please respond, don't bash the fellow asking the question or bash him again when he resonds to someone who did not even come close to answering the original question. Like I said just look at how fast this thread got off subject and stayed that way.

 

[FlyBoyMark]

Re: Mercury - 40 to 50 HP by changing the carb

Maybe..converted my 3 cylinder Mercury 40 HP to 50 HP. Required 3 new carbs, new higher volume oil injection pump, plastic tee for oil injection line and removal of reed stops then tune up..cost of $375 bucks, recouped 150 bucks for sale of used parts with 100 hrs use in fresh water only. Jumped 2" of pitch and 5 mph @ same RPM for my application. I only did it because I got my 2001 Mercury 40 HP for $2,500.00 bucks new.<br /> You have to study Mercury's parts list very carefully, you can over look very suttle differences in the listings easily. Mercury bought Force and criss crossed alot of the parts in different lines. Supposedly, all the late 3 cylinder 40 hp, 50 HP and 60 HP blocks are of Force origin....The 60 HP has some extra port work over the 40 and 50 HP. Aside from that they are identicle on the outside of the block and can interchange on the motor legs...

 

[merc_500]

Re: Mercury - 40 to 50 HP by changing the carb

Originally posted by laybackman:<br /> merc_500: Consider your reply and then please read the first item in this thread. Apparently you didn't. The 50hp carb HAS a larger jet already AND it's throat IS bigger to match that larger jet so the fuel/air mix is correct but delivers more volume than the 40hp carb. By the way if you jet the 40hp carb and remain at the same altitude it will run fine but rich until the leg goes in the water and when you put the motor in gear it will bog because jetting only gets you more fuel but not more air. Is that understandable to you??

OK listen buddy, if you dont want to hear any opinions other than what you think will work, then go out there and put that bigger carb on. <br /><br />I'm telling you from experience with snowmobiles, dirtbikes, and shifter-karts, just adding a bigger carb WILL not gain you 10HP. If it did dont you think the manufacturers would be doing that? <br /><br />Adding a larger carb with increased jetting will just give ur merc a bog. Trust me i know. I had an '89 Ski-doo with a 462 engine. I had a set of 34mm carbs, and 40mm carbs.<br /><br />For fun, i put on the 40's, left all the jetting stock for the 521 motor they were off of. Let me put it this way, the engine ran like ****, terrible gas mileage, bad low end bogs, etc.... <br /><br />Motors are meant to run with there factory carbs, not with oversize carbs and large jetting allowing to much fuel/air ratio. Unless, as i stated earlier, you accompany the large carb with other modifications to the motor. <br /><br />Is that understandable to you?

 

[FlyBoyMark]

Re: Mercury - 40 to 50 HP by changing the carb

Merc..I think what he's getting at is there ARE some engines(as in my case..) that DO only have to have a bigger carb such as late Merc 40 to 50 HP or Merc 20 HP to 25 HP. He's asking if his engine is one of those FEW engines that it can be done to or are there other changes needed.

 

[laybackman]

Re: Mercury - 40 to 50 HP by changing the carb

Merc_500<br />I will ask you for a large favor. Please read my first post again. See what I said and asked. Then read my last post again. Now what you experienced with those particular engines has absolutely no bearing on what I said, or asked, in those two posts. I will listen to ANYTHING anyone has to say ONLY if it relates to the particular question asked. You last post mentions snowobiles, dirt bikes, and shifter-karts. Unless any of these are powered by a mercury outboard, how is anything you say helping me with my one and only question? "Are there any STOCK changes that are not listed in their factory manual or parts list?"