My 1944 R/Enfield WD/co has recently developed a rather strange issue. When the engine comes under load (Hills) about 3/4 throttle 35-40mph, it coughs and stutters for a few seconds. It does have a "Talflow" Airbox fitted but used to be fine with it. I noticed the plug was very sooty and dropped the needle 1 notch, which has made it much better but not completely cured it.The plug looks better (but maybe still a bit sooty). I have cleaned out the float bowl which did have some debris at the bottom. any ideas would be helpful please - I have now put fresh petrol in.
Thanks
Gary