[Mgs] Unsteady timing

[Paul Hunt]

Timing jitter can be caused by a worn timing chain and gears or worn
distributor, or a non-operational timing chain tensioner.  Bit difficult to
check the former now, new distributor noted but check for sideways play in the
shaft and check that when you turn the rotor anti-clockwise by hand it is
against spring pressure and it returns all the way leaving no slop.

If you can't get the idle below 800rpm the carb butterflies aren't closing
properly, or possibly the throttle spindle shafts and bushings are badly worn
It's NOT a vacuum leak, an engine can't run on air alone, if it is running
then some fuel must be getting past the butterflies i.e. they aren't fully
closed.  They could be hanging on the cable, there should be a little
free-play in the cable when released.  The interconnecting shaft clamps could
be misaligned i.e. the air-flow isn't balanced, slacken the clamps and try
again.  Assuming the idle screws are backed off from the stop, make sure the
fast-idle screws are also clear of the choke cams.  If the engine is still
running it can only be butterflies or worn spindles, although if you have the
poppet valves they could also be leaking, solder them up.

PaulH.
  ----- Original Message -----
  I am having a problem setting the timing on my newly rebuild engine.  It
seems
  to jump around plus or minus 5 degrees.

  ...  I can't get it to idle any lower