Quadrajet

[mocwon]

I am struggling like a big dog with the Quadrajet on my 72 GMC. The carb has stamped on it that it is made by Carter for Rochester. I put a kit in the carb (for models 4MC - 4MV) but it seems to me the accelerator pump is sticking in the bore. I get some gas coming up around the stem that comes through the top of the carb. This thing runs like crap and won't idle for squat. I tried matching the numbers on the carb with any number of websites to see if this is the right carb for the truck but I keep coming up with no match. The numbers are the carb are 6373S on one line and 898 on the second line. These numbers are stamped on the driver side just like what I see on the websites. I am guessing this is not the original carb; am I right? I have always run Holleys and Demons so I am a novice with the Quadrajet. I am beginning to understand why I hear alot of negative comments about these beasts. Any tricks to getting this thing acting properly would be greatly appreciated. Thanks for your help......

[ckhd]

If fuel is coming out of the top, there can only be three things wrong, either the float is not adjusted right, the float has a leak and 'sunk', or there is a piece of crud under the needle which won't let it stop the fuel flowing into the carb. Most likely a piece of crud, unless it was doing this before you did the rebuild.

The numbers you have are not the identification numbers. The right number will either start with 70 or 170. On the carbs made by Carter, some had the number on a metal tag... that someone probably lost before you ever got the carb.

There is nothing wrong with Q-jets. The people who complain about them just don't understand them and don't have them set up right. The ONLY thing I'd take over a Quadrajet is a good port injection system.

[Frank_Zeller]

The top might be warped. Common on older q-jet. Make sure the vacuum break hold the secondary air flaps tightly closed at idle. (this prevents the bog) The U shaped wire that holds the float down should be bent up such that it hits the air horn a little. This insures that the float stays put and works correctly. Set the float to 1/4. Set the mixture screws out to 4 turns. Make sure you have the correct base gasket too. Flip carb over and check that its the right one. The q-jets use about 4 different types.