Originally Posted by segapet
Wondering if anyone has an idea as to why when I switch off the ignition and remove the key the fairlane keeps running? I also removed the battery cables and 3 of the plug leads before stalling it with the clutch! Would appreciate any assistance! It is a 68 zb fairlane custom, 221 cubic inch 3 spd manual column shift!
The problem you have is called 'run-on'. It is the result of carbon build-up in the heads and tops of the pistons. The root cause is excessive oil consumption from rings and valve seals.
Three old timer ways to deal with it, and one less familiar 21st century solution that could also be used on vintage iron.
1. A coke bottle filled with water. Remove the air cleaner, bring the idle up to about 1500 RPM and very slowly
pour the water down the carb with your thumb over the neck of the bottle to let it trickle out
. This is important. If you pour too fast, you will fill a cylinder with water and, well the results will be very unlucky.
2. Pull the heads off, clean the chambers, the crossover heat riser in the intake manifold (probably carbon'ed up from age mostly) and tops of the pistons, then reassembly. More work, but not too difficult.
3. Taking a page from the 21st century, find a direct rubber vacuum line to the intake manifold (there should be a large vacuum tap at the back of the manifold that the vacuum wipers attach to) and attach a aerosol can of engine combustion chamber cleaner. Similar to option 1, but has, in addition to water, a cleaning chemical that dissolves carbon on valves, pistons and heads.