Why multiple carbs?

hibbert6

Petty Officer 1st Class
Joined
Jul 15, 2006
Messages
323
Why do outboards use multiple carbs, if keeping them tuned/timed/whatever is such a hassle? I know many sports cars used to do that, too, but why not a single carb (maybe a progressive 4 bbl) and an intake manifold, like most cars w/o fuel injection have?

Dave
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Why multiple carbs?

because most are 2 strokes, the small 2 cylinders have single carbs, but the larger has multiple carbs, one for each cylinder.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Why multiple carbs?

More power from less weight and displacement; plain and simple. Just like high performance pre-EFI car engines.
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Re: Why multiple carbs?

On 2 stroke motors the length of each intake manifold runner is critical to the operation. With a seperate carb for each cylinder allows each manifold length to be exactly the same. the 2 strokes also use much shorter manifold lengths. note the long manifold runners on the new 4 stroke motors allowing for better torque/low end performance. Good Luck!
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Why multiple carbs?

Carbs are not a problem but people make them a problem by not using fuel system treatments like Stabil or Sea Foam. They simply neglect the fuel system which gums up the carbs, causes the engine to run lean and then a burn down occurs. It is so simple and comparatively inexpensive to use the stuff religiously.
 

coolguy147

Commander
Joined
Jul 14, 2008
Messages
2,817
Re: Why multiple carbs?

thats why i put stabil in my mercury and let it sit like a good boy:D
 
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