I had a similar problem a few years ago. I spoke to a lawnmower repair guy who had just retired. The trick is to take out the spark plug and pour about 1 teaspoonful of petrol directly into the cylinder through the spark plug hole. Put the plug back, then start the engine normally. Apparently the initial ignition sucks the grot out of the carb & burns it up - no need to strip the thing down. This works for me every year. I've had my Mountfield for over 20 years, and it's been serviced twice - 3 times if you count the one I'm doing now!
happy hobbit
March 2009
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