Another NC50 carb issue....

[737pilot]

Ok, I have read all the other threads. I have cleaned my carb about 4 times now. Checked timing, points, changed mufflers, compression, everything I can. My NC50 will only stay running with the choke on. And even then it doesn't run well. Advice? I have checked all the tubes, holes, jets, etc in the carb, ran small wires through all holes. Nothing helps.

I pulled the spark plug and it seemed very long, and the gap was very small. So I pulled my plug from my other NC50 that runs very well and put it in this one (this plug is much shorter and gap is correct). Now it won't start at all with this correct plug with proper gap. So I take it out and put it back in the NC50 that runs well and then put the long one back in after I gap it correctly. The piston comes up and just touches the electrode enough to close the gapa bit and it will run, but only with the choke and not too well at that.

So, with the wrong plug it runs, but not well and only with choke on. With correct plug and gap, won't even start. Help!!!!! Advice anyone? Thanks.

Mike