The pilot screws on the 670 motor are ahead of the slides which mean they are adjusting the the amount of air. Turned in means more fuel, turned out means more air.:)
Pilot screws adjust the amount of air drawn into the pilot circuit. The more they are turned in, the richer the fuel mixture. Wht is the rpm that the machine idles at after it settles down?
As a partner in a local service shop, I have the upmost respect for all parts personell.:d The daunting task of making the customer happy and providing an environment for the bussiness to be respected is a hard thing to do.
They all take pride in the work they do and are under appreciated. If...
Can also be the throttle override kicking in. Make sure machine is warmed up before giving her guns. Also sometimes backfires when first started as this is a normal occurance for this ignition system.:)