Timing / idle irregularities

[302Z28]

After replacing a burnt exhaust valve, I attempted to set the idle speed and ignition timing on my '92 Metro 1.0L.
When setting the idle speed, the spare fuse is installed in the appropriate recepticle in the fuse box. The idle speed has been set to 800 RPM. When the fuse is removed, the idle jumps to around 1100 RPM.
When setting the timing, a jumper wire is placed across the two terminals as per the underhood diagram. The timing is set at 5 degrees BTDC at 800 RPM. When the jumper wire is removed, the timing advances to 14 degrees BTDC and the idle speed jumps to 1100 RPM. It seems difficult to believe that 300 RPM increase would result in a 9 degree timing advance.
When pulling up to a stop sign, the idle is very slow to decrease, about 20 seconds, then it will only drop to 1100 RPM.
Could these two problems be related, or is one causing the other?
Any ideas would be greatly appreciated.
Thanks,