The Stovebolt Site Forums The Shop Area Engine Shop 2g jetting

Hey guys. What size jets should I be running in my 2g carb on my 61 283 stock other than an hei down here in florida. its running rich and I have the idle screws all the way in which is where it runs the best. I don't know what size is in there and I didn't want to take it apart until I got some new ones which I have to order. If I do have to take it apart does it tell me what size they are or do I have to measre? do I just check the diameter of the hole. Jetting is definetly not my area.

If it has suddenly gotten rich, it's probably not a jetting problem. Chances are you've got a leaky needle valve/seat assembly, or a float that has gotten some gas in it and can't seal the incoming gas well enough to keep the fuel level in the float chamber correct. A high fuel level will result in a rich-running condition. You could also have a sticky power valve that's letting fuel bypass the main jets. Either, or both conditions will make the engine run very rich and use lots of gas!
Jerry

its been rich as long as I have had it. I have had it apart a couple of times and jetting is the last thing it could be. the po lived in north carolina when he had a new carb put on it so I am thinking that it was jetted for a higher elivation

Replacement jets for a 2G aren't very common parts. Somebody like CarbKing might be able to help you out. If you use a set of number drills and get a guesstimate of the size jets that are in there now, that would be the only way I know to figure out which way to jump for a leaner mixture.
Jerry

thanks jerry I work in a machine shop so I can just pop them out and check them with a pin gage. I found a place that sells individual parts online finally. Thats why its been rich for so long. I couldn't find anyone who sold them. I read somewhere to try two sizes smaller if its to rich. Is that .002 thousanths?

Those jets should be numbered.

Carburetor model B, BC, BV, 2G,2GC,4G,4GC are all in the group "A" jets. In this group are three different styles, a 90 degree square cut, a 60 degree approach angle short taper, and a 60 degree approach angle long taper. All three will interchange, just stay in the same sub group. Each jet is stamped with the orifice diameter, which may or may not be the true diameter of the hole. But a decrease in numbers will decrease the size, same for going larger.

By looking in the top side of the jet, you can see the difference in the three styles. Going from the largest hole in the jet to the actual jet orifice, the angle and length of the taper cut is the difference, it effects the fuel flow through them

Joe

It probably has 53-55 in it. They are stamped but when you are my age you need a magnifying glass to read it. It is thousands.

thanks guys. I will take um out and see what the are

it was jetted for a higher elivation

If it was, it would be jetted leaner.

Just a chance: your vacuum piston is carboned up, and the metering rod is stuck in the "up" position (full rich).

The 2G doesn't use a metering rod but the power piston could be stuck or the vacuum passages to it are blocked. The vacuum holds the piston up till the vacuum gets low under accel. & the piston drops to give power enrichment. I would put my money on an incorrect float setting or a float with gas in it.