One often overlooked simple cause for dieseling is that the idle speed is
too high. When you shut off the ignition, there is often still enough
air/fuel mix coming in to allow some hot sopts in the engine to get it to
momenarily fire on one or more cylinders.
A really old timers trick was just prior to shut down, blip the throttle
a time or two and shut off the key then. Seems that the incoming air
with the engine coming down to idle speed, will cool the hot spots and
kill the dieseling.
For the last 25 years or so, nearly all carbureted engines had either an
idle fuel shut off or an idle stop solenoid that came into play as the
ignition was cut. Closed off the supply of air or the fuel to the engine
and they never dieseled.
SU's predate those solutions.
Paul
PAsgeirsson@juno.com
On Tue, 11 May 1999 02:27:31 PDT "andy webster" <trunkie@hotmail.com>
writes:
>
>>Andy,
>>
>>How's the run-on problem coming?
>>WFO Herb
>>
>
>
>Not too good thanks Herb. I tried enriching the mixture a bit by
>turning
>that nut on the bottom of the carbies, but I'm not real sure of what
>I'm
>doing and now its running like a dog. I think I'll take it for a tune
>up at
>a LBC specialist and ask if I can observe and learn the tricks of S.U
>tweaking...Any hints for me? I would prefer to do it myself and keep
>the
>cash
>Andy
>
>
>
>
>
>>
>
>
>> > Herb
>> > I would have if I hadn't done a valve grind just before getting
>the car
>>back
>> > on the road.The bores and piston tops were squeaky clean too.
>> > How fast does buildup build up?
>> > Andy
>> >
>> > >From: HFC <froggi@cdsnet.net>
>> > >Reply-To: froggi@cdsnet.net
>> > >To: andy webster <trunkie@hotmail.com>
>> > >CC: Daniel1312@aol.com, spridgets@autox.team.net
>> > >Subject: Re: Octane & CRs was Re: Automotive calculations for
>dummies
>> > >Date: Sat, 08 May 1999 15:17:10 -0700
>> > >
>> > >Andy,
>> > >
>> > >Did you consider carbon build up?
>> > >WFO Herb
>> > >
>> > >andy webster wrote:
>> > >
>> > > > No fair!
>> > > > I'm getting dieseling after switch-off and I suspect a bit of
>>knocking
>> > >with
>> > > > 96 octane leaded. I've only got ~9:1 CR, whats goin on?
>> > > > Is my ignition timing up the khyber?
>> > > > Andy
>> > > >
>> > > > >From: Daniel1312@aol.com
>> > > > >To: kturk@ala.net, trunkie@hotmail.com,
>spridgets@autox.team.net
>> > > > >Subject: Octane & CRs was Re: Automotive calculations for
>dummies
>> > > > >Date: Sat, 8 May 1999 15:37:54 EDT
>> > > > >
>> > > > >In a message dated 07/5/1999 7:47:31PM, kturk@ala.net
>writes:
>> > > > >
>> > > > ><< Yeah there is nothing about this that should work...
>especially
>>with
>> > >no
>> > > > > lead.....
>> > > > > >>
>> > > > >I am not sure what petrol is used. It might be 98 (English
>method
>>of
>> > > > >calculation) octane unleaded or 95 leaded. I don't think
>they use
>> > > > >additives
>> > > > >but the guys that run 15:1 CRs might.
>> > > > >
>> > > > >For myself I ran 11:1 on standard 95 leaded with no problems
>(on a
>>full
>> > > > >race
>> > > > >mixture strength).
>> > > > >
>> > > > >
>> > > > >Daniel1312
>> > >
>>
>
>
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