Out of time or spark plug wires incorrectly installed.
Incomplete combustion
Start and run, no. Cough, backfire, yes.
On an interference engine you can have internal engine damage when you attempt to start it. On a noninterference engine it may not start or it may backfire, or miss, if it does start.
It's lean. You have to figure out why.
to much fuel is going to the engine for it to burn it all
The timing of the engine is off or the spark plug wires have been hooked up incorrectly.
Normally from an engine backfire. The plug fires when the intake valve is partially open which will explode the fuel in the intake and carb.
AnswerSounds to me that your vehicle is off time. Check the timing on it. If the timing is off it will backfire through the carb and also if it is cross wired (firing order wrong) it will backfire through the carb.
If your engine backfires when trying to start and the valve timing is correct, then it could be electronic ignition unit or the pick up that causes the spark to occur with wrong timing.
your engine will sound rough while at idle speed and your gas milage will start getting worse. it also might start to backfire and make a little more noise than it normally would.
you tell me the year ill tell you why
Could be in need of a tune-up.