Replacing carb question

[soulhawaii]

2004 Merc 4.3l, started dying at idle, fine at throttle. I'm pretty sure it's the carb, just had the plugs and wires / cap replaced 6 months ago.

I don't want to deal with rebuilding the carb, but I can't seem to figure out what my replacement is? A lot of listed carbs say it's for 4.3l Merc but have the single adjustment screw, mine has 2. Are they interchangeable? No numbers on my carb where they should be, I sanded the black paint down and everything

 

[Lou C]

Looks like a Rochester 2GV or the Mercarb version of the same thing. The are easy to rebuild, better to rebuild a good original core than buy a 'remanufactured' Franken carb that you get on line.
Get a book and learn how to do it. Not rocket science...
Here's its big brother the mighty Quadrajet....

 

[Scott06]

Your carb has been replaced previously. With two idle mix screws that is a rochester 2 jet the older brother of the Mercarb your boat came with. The mercarb was merccruisers in house replacement when GM stopped making carbs in the late 80’s early 90’s, not sure if they bought the toolingfrom gm or what but mercrabs have only one idle mix screw…

bottom line you may have a fuel contamination issue that keeps plugging carbs. A lot of folks have issues with the cheaper rebuilds that are out there. Would have a good quality rebuilder like mikes carbs do yours, or if you can find a good local mechanic rebuild yours as there is nothing wrong with a properly rebuilt 2 jet. They are a good basic carb around since late 50’s… i would also remove your fuel filter and check contents for contamination what are the symptoms it is exhibiting?

 

[Scott06]

Looks like a Rochester 2GV or the Mercarb version of the same thing. The are easy to rebuild, better to rebuild a good original core than buy a 'remanufactured' Franken carb that you get on line.
Get a book and learn how to do it. Not rocket science...
Here's its big brother the mighty Quadrajet....
View attachment 371269

Good advice. Theres more pics of Lous quadra jet on the web than miss october…

 

[Lou C]

lol yeah I have posted that one a lot, but I used to think, oh well a Q-Jet is too complex for someone who's not an expert in carbs, it isn't. Only a bit more complex than that Rochester 2bbl.
The fussiest carb I ever worked on was a 3bbl Kehin on my 1980 Honda 1300 Civic. Simplest, the Autolite 2100 2bbl on my 1970 Ford 5.0.
I just don't want people being afraid of carbs when you can sit down with a book and learn how they operate, then take time to understand the physics involved (Bernoulli's Law) and be independent of mechanics. Or, to think your best choice is to buy reman carbs off of various websites, some may be OK but many of them never work right, because they are pieced together from different carbs.
Learn the theory first (pressure difference, low pressure in the venturi vs atmospheric pressure in the bowl) then learn how to rebuild (mostly CLEAN) them....From my Chilton's Repair Manual for American Cars, 1970-1977.


Lastly, dump out what is in your fuel filter/water separator each season and take a good look at it. If you see crud, sediment etc it may be time to clean out your gas tank. Mine looks like this every year...