Gentlemen I got to the field today, with the cowl off, I fueled up the SBACH started it up seemed to run good on the stand, I decided to do a little tuning so I richened the LS and HS 1/8th turn, let it run for a couple of minutes then checked throttle from idle to full, with good throttle response through out. I leaned the HS screw just a hair. I decided to take her up without cowl, I noticed just a slight dropped in RPMS when inverted. I brought her in, richened the HS screw reinstalled the cowl took it back up with just a very slight drop in RPMs. I am going to continue tuning the LS and HS again and see what happens. And for those wondering the MINTOR engines have Walbro carbs, I have tried a three line tank set up (16oz 4titude), my fuel is filtered from my field can to the tank and again between the tank and the carb. I checked the carb screen when I had the engine apart to remove the broken carb bolt, found nothing. Thanks for the advice.