[Fot] Anti Runon Valve ADU9535

[Larry Young]

This question is not of interest to racers, but my street TR250 has had 
a problem with run-on or dieseling since leaded premium went away back 
in the 1980s.  This has continued through several carb rebuilds, many 
ignition configuration changes and recently an engine rebuild.  During 
recent rebuild, I tried to remove any sharp areas that might create hot 
spots and of course all the carbon has been removed, but the problem 
still persists.  There is additional tuning I should and will do such as 
carb rebuilds, carb needles, timing advance curves, etc., but I suspect 
this problem will continue.  The solution for later Triumphs and other 
British cars was the anti run-on valve.  It appears that the simplest 
retrofit would be to install a Rover/MG ADU9535 valve.  Basically, the 
valve opens when the ignition is turned off and floods the manifold with 
air making the mixture too weak to support combustion.  Where do I find 
one of these valves?  They do not appear to be available except on ebay.uk.
Larry