Will check that vent. Looked for the joe pace videos but could not find any from him. I found that the replacement carbs were cheaper than the parts to rebuild one. the cheap ones seem to work, i bought 5 used 3 and still working. Was looking for a site with just the parts that would be cost effective. while i am not an expert, i have not run into a problem like this before. the fact that it will run fine for a couple of minutes then rough, well logic does not apply to this problem, maybe the coil...