This is running-on, or Dieseling, and is caused by the incomung fuel charge
being ignited by pressure and residual heat in the cylinders *after* the
ignition has been switched of. It was a progressively worsening problem as
more emissions changes were made to the engines, and possibly the fuel. The
condition is worsened by carbonisation, shards of metal on the heads and
high idle speeds. Eventually anti-runon valves were fitted which either
dumped air into the inlet manifold, or sucked the fuel out of the carb jets
as the ignition was switched off. I am not sure, without ploughing through
the detail of Clausager, when these were fitted, but after-market items are
available, from the UK MG Owners Club for example.
PaulH.
http://freespace.virgin.net/paul.hunt1/
(or if that URL doesn't work try )
(http://194.168.54.52/paul.hunt1)
-----Original Message-----
From: Tab Julius <tab@penworks.com>
To: mgs@autox.team.net <mgs@autox.team.net>
Date: 09 November 1999 19:10
Subject: What causes "shutoff shudder"?
>
>Turning off my ignition, my 78B's engine will often give me a few shudders
>before it decides to shut off for good. This is an effect I remember
>fondly from other older manual, probably non-fuel-injected cars (most
>notably my long-gone yellow 72 beetle). Releasing the clutch (to a gear)
>causes it to shut off quicker (okay, stall).
>
>Some basic tuning somewhere needs to be done? Or is it just having so much
>fun it doesn't want to stop?
>
>Thanks
>
>- Tab
>
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