50hp carb on 40hp motor?

[JCY]

I own a 2001 Johnson 40hp.I know a guy that has a blown 50hp and he said he'd sell the carb off of it to make mine a 50hp.Is it really that simple.Will changing carbs actually give me 10 more hp just like that.The reason I'd like to do it is because this motor has a jet drive and every bit of hp I could squeeze out of it would be nice.Are there any other tuning differences between the two motors as they are the same blocks.Any help would be great.

 

[DJ]

Re: 50hp carb on 40hp motor?

JCY,<br /><br />It is rarely that simple. The only way to tell is to look at both parts catalogs and compare each part number. That would only tell you component compatibility, not tuning information-which is probably different also.

 

[JCY]

Re: 50hp carb on 40hp motor?

I'm pretty sceptical myself.But if the only difference in the two motors is the carbs then it seems like everybody would do it.The motors have the same displacement and bore and stroke and weigh the same so what what's the difference in the two?Where does that extra 10hp come from?

 

[DJ]

Re: 50hp carb on 40hp motor?

JCY,<br /><br />Many things.<br /><br />Timing<br />Port timing<br />Port design<br />Compression ratio (maybe)<br />Carb. design<br />Jet size<br />Intake manifold<br />Reed plates<br />RPM rating<br /><br />Or a combination of many or all the above.<br /><br />Engine makers price outboards based upon HP ratings.<br /><br />It would only make sense that they would make changes to protect their interests. The most famous comparison is the John/Rude 9.9 to 15.<br /><br />Everything on the outside looks the same, yet they are different animals inside.

 

[Dhadley]

Re: 50hp carb on 40hp motor?

The 50 carb wont do it. In a 40 the reed stops are the restriction. I would spend a couple of bucks for Boyesens, try the carb you have and then try the 50 carb before you buy it. One (thats 1) change at a time.<br /><br />Let us know.

 

[JCY]

Re: 50hp carb on 40hp motor?

10-4 on the one change at a time.The guy I was talking to is a boat mechanic but I just met him recently and don't know much about him although he talks a good game.I almost hate to do anything to the little motor cause it runs like a top as it is but more horses would let me carry more gear in my jet rig.I'm sorry I'm so ignorant about all this stuff but could you please explain a little more about reed stops and what the Boyesens might do for me.The only thing I can do to engines are change starters,alts,etc but nothing in the guts of the motor,although I wish I could.Thanks again guys.

 

[Goodoleboy]

Re: 50hp carb on 40hp motor?

Hey Dehadley!<br /><br />Theis is at least 10000 thousand people that wants to know.<br /><br />What the heck does uh boysen reed do fur us...I got uh forty horse tu..87 model...Evinrude..! now dang it tell us...How tu hopp is sucker up.....PLEASE! Yar admirer....! Goodoleboy!<br /><br />I thank mabey I gat tu much prop fur my motor...!..I aint tried it yet...but if i dont turn 5500 ur so...Iam over proped....mabey...ya think..whut<br /><br />11/3/8...17 pitch....!

 

[bubbakat]

Re: 50hp carb on 40hp motor?

If they can't ask why in the heck do we have a forum like this. I hope that remark doesn't represent your every day attitude

 

[OBJ]

Re: 50hp carb on 40hp motor?

Lee....there have been many posts and threads on the advantages of Boyesen Reeds. Click the search button at the top of the page and do a search. Basically, the reeds are one of the add ons' with 99% more advantage than disadvantages.