I have a Super Punch with a 75cc engine "Bullet" type exhaust and a rear serrated split roller which I was told was made in the mid fifties.
Over the years I have had problems with this and other mowers in that with the throttle flap completely shut it revs too high, yet years ago I remember I could stall the engine by shutting the flap.
I now have a collection of carbs, some of which have worn flap rods which I thought was causing the problem but my present on is quite well fitting. I have also fitted new gaskets to the manifold and each end to the manifold extension tube (sorry if terminology is wrong). I have perviously cleaned the carb and replaced the float chamber gasket.
The engine runs OK but just a bit fast but it would be nice to resolve the problem and any advice appreciated.