How can I convert my 40hp Honda to a 50hp?

[pipedoc01]

I was told with just a little "tweeking" I could convert my 2001 40hp into a 50hp. A dealer told me they were the same motor, same head, and same carburators, but the honda dealer would not tell me how to do it. Is there anyone out there that can help me? pipedoc01@yahoo.com <br />[*]

 

[JB]

Re: How can I convert my 40hp Honda to a 50hp?

We get this question several times a week, Pipedoc. There is always someone who says it can be done, easy and cheap. They all lie. If it was cheap and easy they would tell you how.<br /><br />This is the first time I have seen the Honda mentioned. More commonly it is Mercs, Johnsons, Tohatsus, etc.<br /><br />It would be simpler and less expensive to trade it for a 50. The gain in performance would be hard to notice.<br /><br />Red sky at night. . .<br />JB

 

[capecoralbill]

Re: How can I convert my 40hp Honda to a 50hp?

You did not say who it was that told you it was easy. Let me guess, It was the ahole, whoops, I mean salesman that sold it to you.

 

[Navigator]

Re: How can I convert my 40hp Honda to a 50hp?

pipedoc,<br />I tried this same route with my '00 Honda 40 but found it really wasn't worth it. Like you've already found, no dealer will "Ever" tell you how to "convert" it. I finally did some research and decided that I would just live with the 40 and get the bigger one next time. If you are set on making the conversion (you know it will void the warranty ) what you'll want to do is go out to Ebay and buy the microfische on the 01 model year, then start painstakingly cross referencing the part numbers between both models. It may take you 20 or so hours, but then you will know "Exactly" the differences between the two. With the list of parts you can go back to your dealer and get an idea of the costs involved. At this point, the dealer or preferably the mechanic may be able to guide you with the rest.<br /><br />Good luck and if you decide to convert it, post your findings back on this board. Like JB said, this question has been asked several times before on honda 40's.<br /><br />Nav

 

[Forktail]

Re: How can I convert my 40hp Honda to a 50hp?

I bought a Yamaha 40 hp that was de-tuned to 35 hp.<br /><br />All it took to get it back to 40 was a throttle cam and 5 minutes....$15.00<br /><br />I also have a Yamaha four-stoke 50 hp that I de-tune to 35 hp. <br /><br />Again, just a throttle cam and a few minutes.<br /><br />Now, the Honda 40 makes it's power at 5500 rpm. The Honda 50 makes it's power at 5750 rpm. Same engine, different rpm.<br /><br />So I would guess it's the same thing. Honda probably limits power by using a different throttle cam (governor). Reducing the rpm results in a reduction in power. I highly doubt that Honda would be running so many different carb parts in such similar engines. It wouldn't be cost effective. But I could be wrong.<br /><br />I have a feeling your dealer just doesn't know how to make the change, or wants to take the time to find out. Maybe wants to sell you a new motor?<br /><br />

 

[Fouled Plug]

Re: How can I convert my 40hp Honda to a 50hp?

JB makes a good point, but I will say sometimes it can be both cheap and easy. I own a 1988 Force 9.9 and the only difference between it and the 15 is the carb jet. I pored over the dealer's computer parts file, and the numbers for every other part were the same. Did I convert it? Nope. But it's nice to know I could!

 

[G DANE]

Re: How can I convert my 40hp Honda to a 50hp?

Fouled Plug<br /><br />This is not to start arguing - but<br /><br />I simply dont get it. Every motor runs best when the fuel/air mixture is clousest to 14 to 1. Bringing the mixture up, will cause plugs to foul ( ha-ha ) and bringing the mixture down will cause lean running and damage. I guess there must be some other changes, enabling to use the enriched mixture, otherwise all you get is instabile combustion. Thats my 2 C/W

 

[JB]

Re: How can I convert my 40hp Honda to a 50hp?

I agree with you, G Dane. <br /><br />Increasing the fuel without increasing the air would only produce a lousy running smoke pot. 2 Stroke engines will not tolerate over-rich mixtures. There must be other changes.<br /><br />Red sky at night. . .<br />JB

 

[Bear]

Re: How can I convert my 40hp Honda to a 50hp?

I guess you've all seen this before, it is a lot easier and less expensive to sell the 40 hp and buy a 50 hp.<br />It can be done, but it isn't worth it.<br />new camshaft <br />new carbs<br />new CDI unit<br />The difference between 45 and 50 hp as I recall from the release of the Honda 50 some years ago.<br /><br />/Bear