Not turning off

My 90' clipper won't stop when taking keys out and put alarm it has if something's not shutting off and it's trying to keep running, also when running tick over is around 23000.

Was only fully running with no knocks or bangs last week 🤔🤔

ignition switch comes to mind.

When you say it's not turning off what is it doing exactly…….

Turn key/ignition off and its running the same as if the ignition is still on or stalling and restarting/chugging low idle?  

Either as Briano1234 says ignition switch faulty if running normal.

If chugging and restarting the timing may be way off or to much petrol getting in/mixture to rich, fuel cut off valve not working.

It's chugging as if it's trying to restart but never actually starts

Check the timing marks, have you changed the cambelt or done any work on the timing?

Idle is way to high and that will not help with shutting it off, what carb do you have, Webber or Pierburg?
 

The previous owner had the cam belt changed but I haven't touched the timing 

Still check the static timing on the belt and dissy.

The belt could of jumped a tooth if the tension is not right.

What carb do you have?

Check for any vacum leaks or pipes which have fell off…. post up some pictures incase we can see something as miss.  

It's a pierburg carb I'll add photos later 

I had a Mk2 auto that did this, it had a pierburg too… when you put it into park, the idle went sky high, then over ran for a few seconds when you turned it off. 


I never solved it, I put a 20vt engine in it instead.

My Passat was doing this. It was the dizzy that needed  reset back to stock.
I joined this site as I have the 8V 1.8 petrol engine it.
I'm trying to bring it back to life, and "rubjohnny" from this site has been very useful in my restoration! :')

Dieseling after start when turning off with a carb is an iffy fuel pump relay, or Carb issue or timing.

Does it stop if you drop the clutch in gear?