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My 2011 Mountfield SP414 100CC 2.6 Horse Power Self Propelled lawn mower struggles to start when warm.

Let me explain:

When I take it out of the shed, I simply give it three pushes of the priming bulb, pull the starter cord, and she fires right up on the very first pull - Great.

But, after I've mowed the back lawn, I shut it off and move to the front, and when I go to start it again, it takes about 4-5 pulls to get her to fire up, and when she does she puffs a little bit of black smoke, not much though.

Oh, and if I give it one push of the priming bulb before trying, it will fire up on the first pull, but puff out more black smoke.

Maybe this is normal, perhaps it is even something to do with the fact it only has a few hours on it, but I just want to check!

Thanks in advance,

-Jamie :smile:

Your mower is flooding out. The black smoke you are seeing is caused by a "rich" fuel mixture, probably caused by a leaking gasket at the base of the carb. Check for any signs of wear on the gasket. Check the mounting bolts holding the carb in place. If one is loose, the carb will sit crooked, and you will have a leak. Good luck.

slingblade said:

Your mower is flooding out. The black smoke you are seeing is caused by a "rich" fuel mixture, probably caused by a leaking gasket at the base of the carb. Check for any signs of wear on the gasket. Check the mounting bolts holding the carb in place. If one is loose, the carb will sit crooked, and you will have a leak. Good luck.

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Yep, I knew the black smoke was too much fuel, but didn't know what was causing it.

I'll check the carburettor bolts when it is next out for mowing :thumbsup:

Spark plugs are so cheap I change
Mine a few times between spring and fall - less wear and tear on starters etc

SONOFADOCKER said:

Spark plugs are so cheap I change
Mine a few times between spring and fall - less wear and tear on starters etc

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Can't be the plug, the mower only has 3 hours on it, and I know a spark plug doesn't foul in 3 hours :laughing:

Our car has 77,000 miles on the odometer and still has the original plugs! Starts up first time every time, and still gets great economy :thumbsup: