2008 9.9 to 15 carb

[goatman1]

looking at buying a 9.9 4 stroke with the 15 hp carb
is there an actual improvement with the carb upgrade?

 

[Edchris177]

The major issue is you don’t know if it’s an actual 15hp carb, or a 9.9 that some backyard experimenter re-jetted with 15 parts.
You cannot tell the difference unless you remove the carb & can see the larger Venturi, (throat size) of the 15.
And that assumes you know the size of the 9.9
In order to obtain 15 hp, you need more fuel, more air, & more rpm. If it’s a rejetted 9.9, you are pouring more fuel into the same air volumn…result…a much richer mixture, but no more power.
The 2nd thing…what kind of boat are you putting it on? From 9.9 to 15 is a 50% increase in power. If you have a 16’ Lund tinny, it will be getting on plane with 4 adults. If you have a bigger boat that won’t plane with 15hp, the difference is academic.

 

[goatman1]

i want to put it on a 10 foot livingston, it has a tohatsu 9.8 on it and i just want a little more speed for going up river against a tide
the throat size or venturi is the carb, correct?
i could just grab a digital caliper to measure it
who knows the dimension of the 9.9 and the 15 lol

 

[goatman1]

its a 15hp carb and he has numbered drill bits and oversized the pilot so theres no cold start issues or poor idle
its a heavy motor though tohatsu is 81 pounds and suzuki is 97 pounds found a write up

Four-Stroke, 9.9-hp Outboard Motors Test 2009 - Practical Sailor

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