Help with engine

[John Whyte]

I have a Mackay 30cc petrol engine that i just cannot get to run right, The engine will not tick over properly or for long and at low throttle up to about a third throttle will burble a lot and just die. i have adjusted the mixture settings every way i can but cannot get the low end to run right. above a 1/3 throttle the engine sings and has great power and performance.
I think the plug cap could do with replacing but would this cause just a problem with the low end, i have also cleaned the carb but still the same, could it be the pump diaphram ?.
Any help greatfully received, Oh And before you say get a Zenoah tried that and it will not fit in this model.

Cheers John Whyte.

[Glenn Masters]

Hello John . . check the integrity of the seal where the pick-up exits the crankcase at the rear . . pushing the motor with an electric starter can allow a poor seal whereby air can be drawn in. This makes it impossible to get a correct mixture at idle. Try smothering the seal with good quality silicone sealant - it might help . . . good luck