I have a 25hp Kohler on my 60" ZTR. Had a new short block put on this past winter and ended up having some throttle issues. So I had a new fuel pump put on and needed to replace the valve cover on the oil fill side. Now its a couple weeks later and for the last week periodically it will sound like I am trying to make popcorn. It doesn't do it all the time but it is frequent. Not exactly sure what I should look at first. I am trying to not take it back into the shop since they will take a few days to look at it. Can't afford the down time. Any help would be appreciated.