sorry for not saying thank you, cant find one on amazon, this link you just sent, do I type every thing on link, on carb is what looks like heater unit of some kind, with 2 wires connected to it from auto choke , when engine is running if I touch carb with screwdriver and earth screw driver to frame or engine I get sparks, why, many thanks

ray, January 2015

thanks will try. also just fitted new auto choke

ray, January 2015

You're forgiven - only one in a 100 ever come back to report success or to say thanks - so no matter - and you've been courteous so thanks for the thanks...

To follow the link - highlight it and type the character C (for copy) as you hold down the control key.

Now in a search engine address bar - type Control V (for paste)

And follow the link. (Copy & Paste using Ctrl C & Ctrl V)

I know nothing of scooter engines but what you describe sounds like an auto choke unit....

http://www.pedparts.co.uk/blog/automatic-choke-unit-50cc-mopeds

The carb should not behave as you explain - sparks to the chassis - I would guess the auto choke unit to have a fault and to be shorting battery +ve to the carb body.

Amazon sell an auto choke unit for £4.03 - carriage free!

ZY Gy6 Scooter Carburetor Electric Choke Moped Atv Quad Go Kart 50cc 125cc 150cc Carb

I ride a Honda MSX 125 but do not do maintenance on it.

For £7.28 you could have both a manual and an auto choke unit!

Happy fixing..., January 2015