Wordly Scions (of Zenith?)
I am having problems with a stock '78 Spit ZS carb. It has been
sitting on the shelf for a couple of years (because I couldn't
figure it out back when), and I am attempting to revive it.
Problem: Uncontrollably fast idle. (only after engine warm)
What I've done: Substitute known good carb (everything OK).
I've given the (bad) carb a good "visual", thoroughly checked the
(operation of) the water heated autochoke / fast idle assembly.
I've manually set the choke "off" with car fully warmed up.
No adjustment of the metering needle, or idle mixture adjustment
screw will bring the idle down. The idle speed set screw is (of
course) backed all the way out. It just wants to idle at
2K - 2500 RPM. The car(b) starts easily hot or cold, and runs
pretty well at all road speeds.
I'm thinking air possibly air leak. Throttle bushings OK, Throttle
plate is closing fully. The <lift piston to check mixture while car
is running> test seems to give conflicting results.
Any ideas much appreciated.
Bob Sykes
75, 78, 78 Spitfires
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