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Not necessarily so. It could be real close. I know it doesn't seem like that but with the rpm's up there and the throttle closed they go lean pretty quickly. Fatten it up from where it was originally and see if that doesn't take care of it.




Popping in the exhaust is from fuel igniting in the exhaust system. Briggs and Straton goes so far as to electrically close the main jet on shut-off to prevent backfire in the exhaust on shut-down. Eliminate any air leaks in the exhaust system and eliminate as much fuel as possible. If it doesn't have oxygen and fuel it won't ignite.
Doug