I have a 71 250 Maverick and everytime I gun it off the line it will almost stall out?? I put new plugs,distributor, condensor, and points on about a week ago and reset the timing. When we set the timing to 6 anytime when we gassed it it would backfire out the carb. We set the timing up to around 10 I think and now it has this problem. It was stalling a little off the line before that is why I put all of the stuff on. any help would be appreciated. Thanks William
Take a look at the accelerator pump. Sounds like it is not giving the engine the shot of fuel it needs to get going. If that is good, take a look at the vacuum advance, made sure it works. Take the vacuum line off, take some vacuum on it with the cap off, and see if it advances the distributer. Good luck, and let us know, Earl
These engines were also noted for the carb mounting nuts coming loose and causing a vacum leak, also make sure all other screws are tight on it. The symptoms you describe indicate that there is too much air inducted into the carb and not enough fuel. Also the timing will affect this "lean" condition, use a vacum gauge to see if you are pulling a steady vacum reading and not fluctuating on the dial. Should read around 18 to 20inches, does the timing hold steady when you have the light on it or are the marks fluctuating at idle? The accellerator pump is in the carb, it acts like an old tire pump, as the plunger is depressed air (fuel in this case) is forced out into the fuel delivery circut, if the plunger is torn or hardened up and worn the air/fuel will leak by and reduce the volume delivered. Take a compression reading on each cylinder to verify the overall condition of your engine, also make sure intake mounting bolts/nuts are tight. Use a process of elimination and you will find the gremlins that are causing the problem. Good luck with it.
9 out of 10 times problems like that are vacuum or carburator. Another way to check for vacuum leaks is to listen for a hissing sound. You can take a section of pipe, or hose, and put one end up to your ear, and point the other end around the intake and carb, this will magnify the hissing sound( just make sure your brother/or friend is not in the driver seat waiting to honk the horn like what always happens to me)
I had the same problem with my 302. I rebuilt the carb just to see if that was it and that solved it (it was full of crap). To check to see if it is the accelerator pump, I look into the carb and open and close the throttle (don't look to close or you might get a bunch of gas in your face) . If its working, you will see gasoline being shot into the carb.
