K'plate clipper lumpy revving at low revs

Hi All,

I have a K’ reg clipper which has had a webber carb fitted. The engine was running fine until I decided to give her a service. I started off with the plugs, when replaced revving was lumpy at low revs. At above 1500rpm its responsive and ok. Before placing each plug I sprayed carb cleaner down the ports to clean any carbon in the cylinders. At 1^st I suspected the plugs so I swopped them with the old ones. Still the same issue. I have now swopped them back with the new plugs.  I have had the air filter off and revved the engine and looks like the fuelling from the jet hasn’t got the consistent flow of fuel.

Can anyone suggest what has caused this rough/lumpy revving.

Thank you

Never heard of spray carb cleaner into the cylinders when removing the spark plugs, does not sound a good idea to me as any thing dislodged will end up sitting in the cyinders and possibly scoring the bore? I would remove all the plugs and crank the engine over to expel anything left in there.
Did you make sure all the HT leads are in the right order?

mark1gls said

Never heard of spray carb cleaner into the cylinders when removing the spark plugs, does not sound a good idea to me as any thing dislodged will end up sitting in the cyinders and possibly scoring the bore? I would remove all the plugs and crank the engine over to expel anything left in there.
Did you make sure all the HT leads are in the right order?

Hi Mk1GLS, I would suspect any muck to be forced out through the exhaust ports?