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Mend Mountfield SP470 Mower Engine Spark Plug

Mountfield SP470 Mower fuel mix - too much petrol?

Hi,
Wonder if any one can help. I have a Moutfield SP470 that is running too rich. It works ok from cold, but then as warms up it starts to splutter and the engine doesnt run smooth at all. The spark plug is also becoming very sooty which suggests the fuel/air mix isn't right.

I have looked and there doesnt appear to be any way of adjusting the mix. Can anyone help?

Mark
July 2011
MountfieldMountfield SP470Garden Tools, Lawn MowersMower Engine Spark Plug
Same here, I replaced the Diaphragm and its still the same. Just wondering if it could be the carb gasket.

Dave
August 2011
Hi Phil,

Thanks for the answer. I replaced the carburettor diaphragm but it when I removed it it looked ok. Replaced it anyway but problem still exists.

Any other ideas?

Mark
July 2011
Replace the carburettor diaphragm. Fixes this problem 99% of the time.

phil_saunders(a)bigfoot.com

Phil Saunders
July 2011

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Mountfield SP470 Running Rich - Help!