Hello, having some troubles with my Carter AFB carb. I have installed/rewired my ignition system and rebuilt my carb. Went to start it yesterday, cranked over and started but after cranking throttles real high. Turn it off and flames backfire through the carb. I've backed the idle/mixture screws out and adjusted the accelerator pump linkage and still had the same problem. Any other adjustments I can make to fix my problem? Also replaced the mechanical fuel pump, old one was seized up and not pumping.

 

"Went to start it yesterday, cranked over and started but after cranking throttles real high." I hope I am correct that that this means the idle is too high. If not please clarify.

Year and engine is always pertinent info. Have you set the timing? When you adjust the mixture screws does the engine idle respond to the change? When you adjust the idle screw does the engine idle respond to the change? The accelerator pump/linkage should not effect the idle.

 

I'm sorry, what I meant to say is that it doesn't idle and It's a 76 D100 with 318 5.2L. After cranking and it does start but immediately it will rev super high almost as if you have the pedal to the floor. Throttle linkage is set right, but I am wondering would could cause this. A couple of friends have told me my floats are sticking but they are set at 7/16" listed in the specs of my rebuild kit. During my rebuild of the carb I just cleaned it and replaced the gaskets. Someone also suggested that it's my ignition. I have put a Jegs "orange" box controller on it and replaced the harness. My timing is correct, its about 3 degrees after TDC. Adjusting the Idle mixture screws did not affect this problem at all.

 

3*after tdc don't sound right. your time should be more like 10* before tdc. this could be causing your problem. if not your problem might be with the choke.

 

Check the high idle screw(choke rpms)and make sure it is not the problem.
Check the rest of the carb linkages and make sure they are not a problem.

 

I have never heard of a 318 with a timing set after top dead center and I have books back thru 1952. Either the distributer has been removed and reinstalled improperly or your timing is wrong. An engine that idles high when first started is quite normal. What RPM are we talking about?

 

Well, had some spare time this weekend and discovered some things. First, my high idle linkage was set wrong. Second, floats needed to be readjusted and lastly the timing was off (of course). After readjusting everything I found I still have the problem. I let it run for a couple of seconds before shutting down and the Tach maxed out at/around 4600 rpms. I'm beginning to suspect that the Jegs ignition controller may have something to do with the problem, but couldn't get the stock unit to even fire, had spark but wouldn't start. Or quite possibly maybe my vacuum advance has something to do with it. Will keep delving deeper.

 

if you suspect you are having problems with the vacuum advance just unplug it and cap the line but from the sounds of it that is not your problem. are you sure all your spark plug wires are in the right spot? was the choke on or off when it was at 4600rpm?

 

Well I rebuilt the distributor and am starting to think that maybe the vacuum advance was installed improperly. I have not connected the line ever since the first time I cranked the motor over and this problem occurred. Yes, I've double checked the position of the wires on the distributor. The carburetor has electronic choke and is currently not hooked up, but I have the choke plate partially closed.

 

do you have the vacuum advance line plugged since you got the vacuum advance disconnected? have you checked for vacuum leaks because that will cause your truck to idle higher.