I am putting a new Sean Murphy q-jet with elec. choke on my buddies blazer and it doesnt want to run right. I put the carb on and when I start it the idle stays at about 1100 rpms, even with the choke disconnected and the idle screw backed off. I have tried adjusting the idle mixture srews and even with them tightened all the way down it still idles high. Also when you shut the truck off it diesels and shoots gas back out of the carb. The carb was built for this engine and should be able to run right out of the box, so what is going on with it? Please help because I dont know how to adjust carbs all that well.