Runs fine for a while and the looses power. It Sounds like it’s not getting fuel and does this even while im stopped, gas it and it reeves up OK but then it’s just reeves down to almost an idle sputters and then reeves up again. When in gear the power drops way off and feels like its gonna stall out, I back off everything and give it while then it comes back again, can’t be trusted at all.
Mine does this as well, give it a few seconds or a minute. It clears up and runs great again. Feels like a fuel issue but i haven't figured it out yet.
Mark all lines at filter head for location, pinch off line from tank, remove and disassemble entire filter head, blow thru and verify zero debris in inlet port all the way to where filter pushes on. Search "3972" on here for pictures and tons of your issue amongst all compact machines.