more then 1 carb?

[jaymasta]

hey guys I was just thinking the other day, so many cars trucks used to have carbs, and many vehicles exceeding 100hp would only have one carb single barrel, any vehicle that had more then one would usually be putting out some serious HP, like my truck has 1 carb 2 barrels, and it puts out 160hp, 170lb tq, so Iam curious as to why outboards have 2,3 and 4 carbs when the HP output is no where near that of a cars output with a single 2 barrel carb or even 1 barrel? when you bring all the linc/sync issues and trying to troublshoot problems and have 3 carbs to look at it seems a little much but there must be a reason for it...?

 

[JB]

Re: more then 1 carb?

Multiple carbs allow what cubic inches you have to breathe better and make more hp per cubic inch, Jay. You aren't going to get 160HP from 50 to 70 cubic inches, no matter how many carbs you put on her.

 

[Chinewalker]

Re: more then 1 carb?

Also, running a multiple cylinder, vertcle motor with a single carb often leads to one or more cylinders running richer/leaner than others. Force offered some 3-cylinders with one carb and they had issues related to this. Merc also had issues with their 3-cylinder models, running 2 carbs. in the 1970s and 1980s. The motors just run better and longer with each cylinder getting its own carb, or one carb evently feeding at most two cylinders.

Also, you can look at it as seperate barrels rather than seperate carbs. Each cylinder gets the best mixture by having a barrel devoted to it and it alone. Even the crossflow V4s with two carbs are running four barrels, with each barrel running its own jetting independently of the others.

- Scott