popping sound

hello, I have checked the plugs. they are fine. switched them and it still happens in the third carb. while the motor was running took a light tester and stuck it in the coil wire against the plug and the popping sound stops completely and the motor runs fine. Take it out and runs rough and pops again. I have pulled the plug wire off while running and motor does not bogg down like other two do. There is deffinately spark in the wire saw it good when using the tester and got a hell of jolt when not using pliers to pull the wire off. haha. dummy. i switched coils from third to second. popping sound was still there but not as bad. looked in at reeds and couldnt see anything bad all looked fine. If this is a stuck vavle, how would i fix this. Thanks

There are no valves(intake/exhaust) to get stuck, this is a two stroke engine. Only the reeds. You need to remove the carb and look closely at the reeds for cracks and or not closed while at rest.

could this be because of low compression???

Have you done a compression test?

no I have not the guy i got it from said he did and said it was low but not too low. i havent got a tester for that yet

Profle? You might be close to someone who can help.You really need to do a compression test.Auto Zone or any chain store might lend you a tester.
With low compression lots of UGLY things can happen, most costly.
If you bought a motor from someone who knew it had low compression.He didn't do you any favors.Hope you got it cheap!!!
Don't know why the popping stops when you poke it.Start looking at ALL the connections for loose wires.It might be a bad ground.J