Marine carb vs Street Carb

[blueroo]

So while I was on Holley's website looking at 2V carbs, I came across two carbs of interest...

First is the 350cfm street carb. Don't really need an explanation here

Second was a 300cfm marine carb. I noted two differences aside from the obvious ones of the marine carb being 50 cfm smaller and a lot more expensive.

The first is the vent tubes. The have a j-shape that redirects fumes and spilt fuel back into the carb. The second is something about them being calibrated "specifically for the loads of a marine engine"


Then on a website selling the 300cfm carb was this disclaimer...

"Marine carbs should NEVER be used on a street application"



What I'm curious about is why can't you use a marine carb in a street application. I'd really like to get a 2V carb but the 350cfm number kind of worries me of it being too much for my motor. But then again, the price tag of the 300cfm marine carb DOES worry my wallet.


Any input?

 

[wallaka]

The "350 cfm" 2-v carbs actually only flow 210 or so cfm when measured like a 4-v. It's not too much carb.

 

[jamyers]

I don't know why you wouldn't use a marine carb on a car, apart from the different jetting, which will probably be far richer than for a car. Maybe that's why they're saying that, because they don't want to get into trouble with the EPA-types.

Now, I wouldn't use a car carb on a boat, and I'd be EXTREMELY hesitant to use a Holley with their goofy float-height-setting method, and other goofy design issues.

 

[60s Refugee]

I have a friend who took the GM 350 from his 1979 boat and put it in his car. The original set up was called a "Mercruiser 260". The 260 means 260 horse! It had no pollution controls, a mild cam, and a four barrel. He had to swap out the marine water pump and exhaust manifolds, but it ran great. Other than that it was a car engine. I would not suppose that the carb would be any different either, comparing it to the exact matching auto carb.
Harry

 

[frogmn666]

Marine equipment is supposed to be spark free. A marine start solenoid cannot generate an external spark in the engine compartment. My guess is that marine carbs do not emit fumes that are easily ignited. If the jetting is right, there is no reason to not use a marine carb on a street vehicle.

 

[quaddriver]

they would work but I would change the jetting....since a boat must always run in an overfueled condition, it will be a bit richer to not burn/tulip the valves.

the J-vent is to cause any and all fuel slosh to get sucked into the engine and not splashed into the bilge and you end up doing an HMS Hood imitation.

I would never use an auto carb on a boat tho....