If your mower is under powered, you need a bigger one. Contrary to popular belief, increasing the speed on a GOVERNED engine does not increase the power output - it just makes the self-drive work a bit faster. In fact, since the normal position of the carburettor throttle will be open more than it would have been, there will actually be less 'reserve' power available for coping with sudden increases in engine load.
Having said all that, there are limits, and if your mower has a stretched govenor spring, this will cause the engine to run slower than designed, and this may be your problem. The engine speed will need to be checked with a tachometer to be sure.
phil_saunders(a)bigfoot.com
Phil Saunders, September 2009
