Quadrajet Identification

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Free Rochester Quadrajet Manuals

Rochester Quadrajet Carburetor Manual

Application Carburetor Number Carburetor Kit
1974 Oldsmobile Cuslass Toronado 7044280, 7044281, 7044282 4207
1973 Oldsmobile 455″ 7043251, 7043253, 7043252, 7043259, 7043282 4207
1969 Oldsmobile 7029250, 7029251, 7029252, 7029253, 7029254, 7029255 4207

Quadrajet 4 MC, 4 MV Carburetor Trouble Shooting

E4MC, E4ME Adjustment Procedures

 I have a Rochester Quadrajet Marine Carburetor #17059286. It appeared to be flooding at idle and the fuel was leaking excessively from the throttle body linkages (on both left & right side). I assumed the carb needed to be rebuilt and the leaking was normal (from a drain in the carb) when flooded. I rebuilt it using a kit I ordered from you. I reinstalled the carb and I’m having the same issue of fuel leaking from the throttle body linkages. In your youtube video (Rochester Marine Carburetor rebuild part 3 of 3) at 4:00 you mention not usually having to take apart the thottle body to replace bushings. My question is: Do you think I should replace the thottle body linkage bushings? And if so, do you carry the kit? I think this is what I need to do. However, I read a post online that said the fuel at the thottlebody should already be atomized, and should therefore not leak out the linkage,and that would indicate that the carb is flooding due to the float not being adjusted properly. I set the float to 3/16 like the instructions stated. Any thoughts on this would be greatly appreciated.

Your problem is not bushings. The carburetor is simply puking out too much fuel. The bushings are replaced only if you have excessive free play in the throttle shaft. Flooding fuel will leak out anywhere it can and onto the throttle valves and out the shaft is the 1st place fuel likes to go.

Too much fuel boils down to getting too much in the float bowl. Did you test the (brass) float for leaks? Immerse the float in hot water and if there are any leaks, it will bubble. If you have a Nitrophyl float (black plastic kind of thing), replace it. They absorb fuel over time.

Did you put the fiber washer where the seat screws into the float bowl.

Many times after rebuilding a carburetor and after re-starting the engine, crud from the tank and the fuel lines will rush up to the carburetor and into the needle & seat causing it to stick open. Take the carburetor apart and wash out the needle & seat and try again.

Manually move the float up and down and watch for any kind of rubbing, or catching. Also watch the needle to make sure it is move straight up and down and not getting caught up.

Too much fuel pump pressure could be holding the needle open. Any chance you replaced the pump with a new one? New pumps are always suspect because they come from China and they don’t seem to care about specifications very much yet.

These are just a few ideas, but bottom line is that too much fuel is getting into the float bowl.