at what speed does the mechanical advance begin to kick in?
-----Original Message-----
>From: PaulHunt73 <paulhunt73@virginmedia.com>
>Sent: Jul 4, 2013 11:32 AM
>To: Bill Mills <bmills46@earthlink.net>, mgs@autox.team.net
>Subject: Re: [Mgs] Dynamic timing 74 B
>
>Consensus? You must be joking!
>
>You are right to get the ignition right before tackling the carbs, but that
>really relates to fixing any defects causing misfiring which can confuse the
>issue when you are trying to setup the carbs. A North American 74 (chrome
>bumper) had an 18V 672/673 engine with a 25D4 41491 distributor. That had a
>static timing of 6 degrees BTDC and a dynamic of 11 degrees at 1500rpm. So
>if your idle is 1400 to 1500 rpm that's half the job done for you :o)
>
>There can be a number of things that can cause a high idle as well as worn
>throttle spindles and bushings, such as incorrectly set linkages such that
>one butterfly completely closed is holding the other open, a butterfly not
>fully seating in the throat, poppet valves in a butterfly not fully closed,
>insufficient free play in the throttle cable holding the butterflies open,
>as well as incorrectly set idle and fast idle screws. One thing that
>*can't* cause it despite many claims to the contrary is a vacuum leak. A
>vacuum leak *will* cause a high idle for a given throttle opening, but an
>engine cannot run on air alone, and you should always be able to stall an
>engine with the idle screws - *if* everything else above is correct - even
>if there is a vacuum leak.
>
>PaulH.
>
>----- Original Message -----
>>... What is the consensus of what the dynamic timing should be set with
>>vacuum advance disconnected and plugged off??
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