I have a Suffolk punch rotary mower it's 4 stroke, I left it running for 10 minutes to warm up as I always do. Then I moved it to the lawn. It cut out and just cuts out now after seconds if that. I have checked the spark plug, fuel line and air filter. All of this is ok yet it still feels to me like it's starved of fuel? Maybe the carb??? If not what?

Matthew, June 2012

Well the water in the float bowl is what I'm hoping for, and am going to do that today, would the engine run for 5 or ten seconds with a coil gone??

Matthew, June 2012

Has the mower been left outside? Most often, this is caused by a blob of water in the bottom of the tank (carb-on-the-tank engines), or in the float bowl ('Quantum' type engines).

FYI there is no good reason to warm up the engine for 10 mins. 1 minute is easily enough - just a waste of fuel to do otherwise, and certainly it should not be left idling. Cooling air flow is reduced by the square of the speed reduction, whereas heat production is directly proportional. IE 1/2 the engine speed, 1/4 the air flow. Conclusion - left to it's own devices. and idling mower engine will eventually overheat and blow the head gasket - or possibly cook the ignition coil, which IS a common failure, and may possibly be your problem.

phil_saunders(a)bigfoot.com

Phil Saunders, June 2012