Cut out switch

[Mark63]

I have a1966 LI 125 series 3, and the cut-out switch/button when depressed is not cutting out the engine (keeps running) Is this a common problem, and is there an easy fix, or will I have to take off the headset top to investigate. I am new to Lambretta's and any advice will be much appreciated. Mark C.

[Tractorman]

Easy enough to check, just remove headset top. To test the button, pull the wire to the button out the connector block and connect it to a multi-meter then earth the other lead from the multi-meter to a good earth. With the multi-meter set to ohms press the button and you should have a good circuit. If this is OK the wiring to the CDI may be at fault.

[dickie]

Or put another way, the cut out switch connects the green terminal on the CDI to ground. You can find where the fault is by earthing the various connection points between the CDI and the headset. There aren't too many: off the top of my head; green at the CDI; next connection is actually on the switch. I think that's all.

[hullygully]

clean the buttons clamp to headset area for a good earth too

[missing lynx]

With the engine running remove the green wire that comes from the loom into the headset then touch it to earth if the engine stops it's the button if not it's elsewhere. If it's the button check it's earthing properly and it's not corroded if not work back from the headset you'll probably find a broken wire or a loose wire

[Mark63]

Cheers guys for all your advice, much appreciated.