sure appreciate the help and thanks for the welcome. Its very weird. This thing runs great until you have to do a lot of dirving in one day. Then it gets real bad. It loses power, have to half choke at red lights to keep it running. And then eventually it will die. The only way I can get it started is to turn off the electronic fuel pump or else it floods and Im stcuk for a good 10 min. The back fire always comes at the end of at least a 30 minute drive. It does it when I kill it.
I recently replaced the coil with internal resistor, the plugs, had the carb rebuilt. Last year put new wires, cap and rotor.
Also, my dad put a tumbler and ignition switch on it about a year ago.
Any help would be greatly appreciated.
Probably not the ignitor. They are a go/ no-go type of failure. Could be a failing coil or ballast resistor.
The fuel pump might be wired into the ignition circuit, so it is stealing amperage from the ignition coil circuit. It should be relayed from a switched ignition source.
The backfire after shutdown could indicate the carb is too hot, possibly because of a defective heat riser, or late ignition timing.
If the electric FP has to be turned off to prevent flooding the carb, then there is something wrong. Pump pressure is too hight, or carb float/needle/seat defective. Easy fix would be to install correct OEM parts.