This engine is / was a special build by Tecumseh Europe for the UK mower company Atco Qualcast who used it on their range of domestic cylinder (reel) mowers. The nearest regular Tecumseh would seem to have been the BH.E or GE35
During its availability it was fitted with Tillotson, Delorto and Tecumseh carburettors. The one that’s giving me grief has a Tecumseh carb.
The story. I serviced it last year and the user says that it started and ran perfectly all season. It’s just come back to me for a service and sharpen. The issue ! Done the sharpen then found that it will only start with a mere sniff of carb cleaner on the air filter. It then runs and idles fine - no hunting at full or idle rpm. Leave it for any longer than about half an hour and it needs carb cleaner to start.
What I’ve done. Despite it running ok , I’ve ultrasonically cleaned the carb and replaced the O rings on the emulsion tube.
Finally checked the valves and found virtually no clearance on the inlet, so lapped and gapped both valves - 6 & 8 thou”.
New plug and checked for choke action and air leaks etc.
Absolutely no difference. Still needs at tiny drop of carb cleaner on the air filter for a cold start.
Before I send it back with a can of dope, What have I missed ??