Mountfield 725M ride on

[Changy]

I deleted my previous post because it was garbled nonsense.

I started to lose my marbles because I couldn't determine why the stop wire had a fluctuating resistance value. I closely examined the last section of the wire, and the insulation had a tiny cut grounding to earth!  It moved slightly when I measured the wire, which caused the fluctuating readings 

[Changy]

The Mountfield rides on! 

I struggled to get it running because it was a mixture of many issues. The coil had a single filament of wire which had rusted onto the kill switch spade and shorted against the engine. The kill switch wire had a tiny cut which kept earthing. The fuel had water contamination, and the coil was so fussy I had to keep adjusting the air gap to achieve optimum spark.

On top of that, the control module had a dry joint 

It now starts on the first turn, and the client is delighted.

[Mick]

That's a good result then Changy, well done on sticking with it and not giving up. 

[plazydays]

I am currently working on a Mountfield 725M and regret that decision. The levers on the carb seem to foul the airbox when you operate the throttle/choke lever causing the butterfly flag to stick in position in the carb. I'v looked and cannot figure out why as it all seems to be in the right place in terms of alignment etc. tried to find a decent diagram and it's like it's a massive secret for this model.