# Converting Evinrude 9.9 to 15



## gflinders (Dec 16, 2008)

Hey everybody, I am new to the forum. I am supposed to be buying a 1988 Evinrude 9.9 tomorrow. The carburetor needs to be rebuilt and so I am thinking of just putting a 15 hp carburetor on there while I am doing it. I called the local Evinrude dealership and they said it was over $300 for a new 15 hp carburetor. Does anyone know where I can get them cheaper or where I can find a used one that I can rebuild? Any advice would be greatly appreciated.
Thanks


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## Gramps (Nov 1, 2007)

I have an '84 Evinrude 9.9, thought about doing the same myself.  However it is more than just the carb; it also includes a reed spacer and exhaust housing. IMO unless you are getting the engine for almost free, trying upgrade to the 15hp rating is not worth it.

P.S. - Working on this engine is very easy.

Take a look at the link below tons & tons of info on your engine.


http://www.sschapterpsa.com/ramblings/Johnson 9.9_15.htm

Edit: Watch ebay for the carbs, saw one go for ~$150 before.


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## gflinders (Dec 16, 2008)

Hey Gramps,
Thank you so much for the information. I had searched the internet before and had read mixed reports whether it was just the carburetor or if the exhaust was also involved. The website link you gave me clears up the confusion and is very helpful. I am appreciative from your help. I guess the next thing that I am wondering is how well will a 9.9 push a Gheenoe classic because I am eventually planning on buying one. If anyone has input that would be great.
Thanks.

P.S. I am getting a killer deal on the motor from a good family friend who tells me that he is never going to use it anymore and he is selling it to donate the money to the scouts for a fund raiser for scout camp. It is a situation where everyone wins.


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## noeettica (Sep 23, 2007)

In my opinion converting wil no doubt give more top end but the smooth running low end will be comprimised ...Velocity through a venturi ...

back in my street VW Racing Days I ran 28mm venturis on the street and 32mm when I went racing 

Dave


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## B.Lee (Apr 29, 2008)

The bigger carb running rough at idle would be true, but these motors have an idle air adjustment to compensate for this. The idel mixture is on the front of the motor. I have a 15, and it runds pretty slick. Hauls the mail too!


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## gflinders (Dec 16, 2008)

Thanks for the replies everybody. If I put a 15 hp carb on there, does the rough idle at low end do any damage? Right now I am leaning towards just rebuilding the 9.9 carb, but obviously if it damages the engine there is no argument.


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## B.Lee (Apr 29, 2008)

No, it won't damage the engine. Two strokes run rougher when the fuel mixture is too rich, smoother as the mixture leans out. As long as the mixture isn't too lean, it won't hurt it.

Too rish will foul plugs and smoke, probably burn too much fuel.

Too lean will burn too hot, melting pistons in the extreme cases.


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## Gramps (Nov 1, 2007)

GF - My classic ran 13 mph fully loaded with the 9.9. That was with a buddy, myself, way to much gear and not hitting optimum RPM's. Never ran it solo but would expect around 18mph.


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