# Johnson 9.9hp to 15hp????



## smallieguy (Apr 7, 2004)

1st off, sorry to the moderators is this is a repeat post.

Does anyone know the exact way to convert a 2000 johnson 
9.9hp short shaft manual start to a 15hp?
Looking for a little more got out of my own way if you know what 
I be sayin'


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## Shortdrift (Apr 5, 2004)

All you have to do is put a 15 hp carb on it and do a bit of re-adjustment. Don't bother with the exhaust port as most of the punch comes from the carb.


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## smallieguy (Apr 7, 2004)

Do you know where I can get a carb. besides Norton marine?


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## papaperch (Apr 12, 2004)

A website by the name of www.smalloutboards.com has an excellent article on this very subject. Scroll down once you get on the site and read what they say.


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## smallieguy (Apr 7, 2004)

Thank You  i guess i'm callin norton.


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## smallieguy (Apr 7, 2004)

Called Norton and Don said they could take care of me right away,so
I got it there the same day and the price was great so it will done asap.
And they are doing the exhaust ports  thanks Shortdrift.
papaperch your post made up my mind, THANKS


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## duckdude (Feb 5, 2005)

i got a 9.9 yamaha 4 stroke can u do the same and i have a 25 mariner can u make that the same way to.


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## smallieguy (Apr 7, 2004)

Take a look at yamahas website and see if they use the same
engine for 9.9 and 15 or 25 and?
that will tell you if you can upgrade the hp.


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## Shortdrift (Apr 5, 2004)

Some are upgradeable and some not. The manufacturer will never tell you but the dealer will.


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## smallieguy (Apr 7, 2004)

this is what i'm talkin about
http://www.yamaha-motor.com/product...year=2005&cat=Two+Stroke+Series&scat=Portable
a close look will tell you that the cid is the same in the 9.9
and the 15 and in the 40 and the 50 and so on.
and yes the dealer will me happy to take your $ but at least have
the knowledge that it can be done before you call him.


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## LiquidTension (Apr 10, 2004)

wouldnt be planning on using that on some 10 hp lakes would we?

soooooo can i take my 40 hp to some 10 hp lakes and just use 1/4 throttle  ???????? i swear not to make a big wake.... oh wait.... the boats not gonna get on plane........ its gonna make a wake just as big as a 15 or 25 hp thats not on plane
hummmm maybe i can get a 50hp carb to throw on there.... that'll fool 'em

just sayin'........ silly restrictions.... what was i thinkin' ...... pffftttttt 

:not ripping smallieguy: just sayin'


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## smallieguy (Apr 7, 2004)

A converted 9.9 to 15 and use it on a 9.9 lake?  
Who me?  
Well I'd never do that.  
Like I'd be the only one in Ohio to ever try that.

No offense taken, I just like to know the answers to questions before
they are asked...ie: can you make a 9.9 a 15 or can you make a 40
a 50.
well yes if the engine specs are the same EXCEPT for carberation
and exhaust and props.
think of a 1970 chevy 350 with a 2barrel carb and then switch it
to a 4barrel.
horsepower will increase, period.


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## Erie Addict (Apr 12, 2004)

It has happened before. I know of a guy running a merc 25 hp with 9.9 stickers on it. he has never been questioned about it.


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## smallieguy (Apr 7, 2004)

Thanks to all for the advise but in the end I desided not to 
have the work done.
It just wouldn't be worth the $


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## WoodenShips (Aug 5, 2004)

smallieguy:
I am going to do the same thing with my JOHNNY 9.9 .I have a SEA NYMPH 17.5 and it's the slowest thing on the lake besides POTOON boats.I have a wooden deck that gives the boat a lot of weight.I'M going to take mine to a place across the river in Wheeling WVA.Those people are very good.Some of the boats on PIEDMONT are really fast for a *9.9 !*


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## smallieguy (Apr 7, 2004)

Thats the truth about the pied.
I had one of the fastest boats on the lake and then went and got a bigger boat.  
slowed me down from 22mph to 16mph on my gps and on good day.


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## WoodenShips (Aug 5, 2004)

smallieguy:
 *22 to 16!!* On a GOOD morning I might hit 10 mph...and in the wind try 6 for me.  ...I have aimed the boat,put my head down ,and shut my eyes when nobody was on the lake because it takes so long......lol.


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## bkr43050 (Apr 5, 2004)

WoodenShips said:


> smallieguy:
> *22 to 16!!* On a GOOD morning I might hit 10 mph...and in the wind try 6 for me.  ...I have aimed the boat,put my head down ,and shut my eyes when nobody was on the lake because it takes so long......lol.


 It sounds like you may have to install a mast and sail on that "wooden ship".


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## smallieguy (Apr 7, 2004)

Heck one day on milton with a 10-15mph tail wind my gps said
24.7 mhp. And yeah it was scarey.


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