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

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