[Healeys] Engine problem

[Ph.J.Aeckerlin]

Friends,
Wednesday last I received my license plates and at last, after 6 and a 
half years, I am able to take my BJ8 out on the road. It's a fantastic 
experience but I have one point which worries me. When I switch the 
ignition off after a run of, say, half an hour, the engine continues to 
run for a few seconds. Very irregular, the engine shakes like hell until 
it dies out. I therefore now put my foot on the brake and release the 
clutch whilst in 1st gear - that does stop the engine but I don't like 
this kind of rough treatment.
The ignition is a 123 electronic ignition, the carbs were synchronized 
by a pro, the engine was overhauled by a pro - what can be the reason 
and what can I do to stop it?
Many thanks in advance for your reaction.
Regards,
Jack Aeckerlin, The Netherlands
1964 BJ8 29432