Hi everyone, I’m having trouble with my Rochester b carb. When I punch the throttle to accelerate the engine stumbles but then gets going . I understand that this is most probably a accelerator pump issue however it’s a rebuild carb floats set correct at 1 9/32” . I haven’t checked the drop if anyone knows what that is ? Am I right in saying the b works on vacuum drop for the accelerator pump? Could the new springs be to harsh I wonder? Background on the vehicle 1964 c10 230 straight six stock New ignition items except points (could this be an issue?) Timing set at 5 advanced with timed vacuum Plug gaps 040 new champions Size 57 jet ran fine on it before rebuild Any help thanks guys! Matt Sent from my iPhone using The H.A.M.B. mobile app
The accelerator pump is not related to the metering rod. The metering rod does work with vacuum, and a spring. You can see if the accelerator pump is working. Leave the engine OFF..remove the air cleaner, look down into the middle of the carb, and open the throttle. You should see a little squirt of fuel. If no squirt, the pump isn't working.
Thanks for the reply . I have checked and the pump is working . I thought maybe it’s not timed right to feed the engine straight away . Seem like it’s almost to late. It doesn’t die just stumbles. Are different grades of springs for the pump do you know ? Sent from my iPhone using The H.A.M.B. mobile app
The spring rate should not affect it too much....although if you mix up the springs, then it won't work right. Make sure it's all assembled correctly. Check for vacuum leaks, and for proper advance function in the distributor, both mechanical and vacuum.
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