Marine Carbs

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pishta

pishta

I know I'm right....
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Holley states "these should never be used on the street" Why? whats the deal besides J tubes and staked throttle shafts?
 
donuuuu....makes little sense

I can CERTAINLY see why you would not run a street carb on a marine engine.
 
I don't know, but I am curious too. I have a 600 Double Pumper marine carb and I am going to run it on the street. One of the vent tubes is broken off. I wonder if the floats are different? I haven't even pulled it apart yet. I think the bushings on the throttle shafts are different too to meet marine regs?
 

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"A marine carb is designed for wide open throttle (WOT), generally has poor transient response. An automotive carb is focused on transient response for good drive-ability. Marine carbs generally do not work well on the street. Some people compensate with a really loose torque converter (like 5000 rpm stall). In the water, the water provides a lot of slippage - on the street that does not exist."


A response I found here.

http://answers.yahoo.com/question/index?qid=20090108125225AApKxea
 
So is the transition circuit in the metering blocks or is it in the venturi slots? Too bad, this 780 CFM 4160 carb (9015) I have looks nice...
 
Just re-tune it, like any carb. The J's are for, if the floats hang open, it bogs the engine, to make you open the cowl, and look for the problem. Gas in a bilge is a no-no. And you can get marine quadrajets with no J's.

They take the dissy, glue a screen in the vent; same on starter and alternater. costs $2, then charge double the price of automotive.

It is for safety, as explosions can happen, but too much $. Just re-tune it.

BTW, I have seen auto carbs on marine; they ran the same as marine did.
 
green1 said:
BTW, I have seen auto carbs on marine; they ran the same as marine did.
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The question is NOT "how they run" but SAFETY. If you've never seen the aftermath of a bilge explosion, you should do some Googleing. Even on our small lakes around here, Pend Oreille and Coeur d Alene, there have been some small boats suffer engine compartment explosions. Two different incidents I can remember resulted in serious burns and or disfigurement. One involved a very attractive young lady.
 
Marine carbs do not have the vacuum fittings either , no vacuum advance in the marine world . I own a boat repair shop and i see auto carbs on boats every once and a while and try to warn people of the danger but shade tree mechanics know it all ( i too have seen a few boat fires ) . Auto motive carbs vent the float bowl into the atmoshere while marine carbs vent back into the top of the venturi .
 
DFootCuda said:
Marine carbs do not have the vacuum fittings either , no vacuum advance in the marine world . I own a boat repair shop and i see auto carbs on boats every once and a while and try to warn people of the danger but shade tree mechanics know it all ( i too have seen a few boat fires ) . Auto motive carbs vent the float bowl into the atmoshere while marine carbs vent back into the top of the venturi .
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DING DING DING! WINNER!

I live on the coast and have come across some smokin hot deals on marine carbs...but w/o vacuum, they're worthless to me.

Most guys around here have 2, 3, or 4 Yamaha 250hp 4 strokes on their boats anyhow (the offshore guys that is)...unless mega $$ is involved then they've got a Viking or similar with several thousand HP diesels.
 
shanker said:
I live on the coast and have come across some smokin hot deals on marine carbs...but w/o vacuum, they're worthless to me.
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Ditto. I bought an Edelbrock marine carb by mistake on ebay. Didn't notice was under listed in "boats", since focusing on the $25 bid since the guy couldn't spell Edelbrock or carburetor (is it mean to prey on illiterates?). I couldn't understand the missing vacuum ports or how I could use on my Dart, nor could a speed shop that sells Edelbrocks. Finally found it was a marine version and sold it for $175 on ebay right at the start of boat season when everybody finds their carbs gummed up. Bummer, since it looked brand new, but cash soothed the hurt. I love to buy new carbs just to play with them, then resell, especially when I find a deal.
 
DFootCuda said:
Marine carbs do not have the vacuum fittings either , no vacuum advance in the marine world . I own a boat repair shop and i see auto carbs on boats every once and a while and try to warn people of the danger but shade tree mechanics know it all ( i too have seen a few boat fires ) . Auto motive carbs vent the float bowl into the atmoshere while marine carbs vent back into the top of the venturi .
Click to expand...

I have a holley 600 double pumper marine carb that I will sell for cheap if you want it.
 
Let me stir this up.

My ex son-in-law bought a chebbie inboard-outboard. Thru-hull exhaust, flappers stuck open, stopped too quick, injested water into #7. Cranked on it, and blew pos terminal off battery, due to hydro-lock.

Made him park it, when I saw auto engine in it; went through and marined it. Different dist, starter, alt. they have screens over vents, to keep sparks inside.

The marine quadrajet, that cost twice as much- stock auto; vac plugged, vac secondaries. It just had a $200 coat of black paint on it. And yes, it came brand name, and had papers-marine.
 
Hah, Shelby Stanga from Ax Men should get in on this, he has a jet boat powered by a 454 Chebby, bet it's got a marine carb.
 
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