Nissan/Tohatsu 9.9 upgrade

[Buzz457]

I know most of you've seen this before (sorry), but I never have specific to my year and model (2004 Nissan NSF9.9B2). I was wanting to rebuild my carburetor and so I've been online looking for parts. All I really wanted was a carburetor float chamber gasket or rebuilt kit. Of all the research I?ve done the only difference I see between my 9.9 and a 15hp carburetor is the two jets, the nozzle and what I believe is an accelerator pump on the 15 and 18. If this is correct, other than maybe a little ?out of the hole? hesitation (due to no accelerator pump), can I just change the jets and nozzle and essentially have a 15hp? Any help on the parts I need and what is really possible would be great. Thanks

 

[TOHATSU GURU]

Re: Nissan/Tohatsu 9.9 upgrade

Nope. Different carb body. You have to buy a 15 hp carb to do it.

 

[pvanv]

Re: Nissan/Tohatsu 9.9 upgrade

Nope. Different carb body. You have to buy a 15 hp carb to do it.

Quite true. Also, if you change the intake silencer, and swap cams, you can go right to 18 hp.

 

[Buzz457]

Re: Nissan/Tohatsu 9.9 upgrade

So I would need to get a 15 carb to go to a 15. If I did that now, what change would I have to make to to the 15 carb (in addition to cam and air silencer) to go to the 18. In other words would it be better to go on to a 18 or could I do it in stages? Where is the best place to get these parts? I have had trouble locating carb parts before.

 

[TOHATSU GURU]

Re: Nissan/Tohatsu 9.9 upgrade

Parts are available from any Nissan or Tohatsu dealer and you cannot convert a 9.9 or a 15 to an 18...The 18 has a different engine block.

 

[pvanv]

Re: Nissan/Tohatsu 9.9 upgrade

You cannot convert the carb. Different throat sizes. You would need the carb for an 18 if you wanted to run as an 18. I believe the current 4-stroke block for the B model is the same across the board for 9.9-15-18, (3H8B011002 CYLINDER-CRANK CASE ASSY MFS9.9/15/18B) but originally varied depending on serial number.