I have a friend who asked me to replace the carb on his pressure washer. It has a Briggs engine with carb #B1499059. I ordered an aftermarket carb at his request. It was an exact match. It does not have an air mixture screw. Put the new one on and it fired up and ran good. He sent me a message today and said it ran good but in under 4 hours he had to refill it 8 times, using waaay more gas than it did before. I've never heard of this. Seems like if it was using excessive gas it would be running rough. Any suggestions?