I have one cylinder not firing correctly. When I pull ignition wires, one at a time, 1,2, and 4 the engine nearly dies. When I pull wire no. 3 there is no change in engine sound, and the spark is weak. Pulled the plug, heavy carbon on it but that isn�t unusual for this engine. Installed a new plug and swapped ignition wires, still missing. Checked the distributor, everything looks good, points at .020�. No tracking or carbon in there. The PO had installed a IAT-4405 vacuum advance distributor,� but the vacuum was never connected, engine seemed to run ok.
Next I checked compression, have 117 dry and 127 wet. Engine intake manifold pressure is 19.5� at an idle of 700 rpm
The engine has an intake manifold leak, detected by carb spray, on the section of the manifold in front of cylinder #3.Could this be the problem?
The carb has been changed from a Solex to a Carter WO 636SA freshly rebuilt by Old Jeep Carbs.
The ignition wires are the new style, not copper, they will be changed. As well as a IAD-4008 distributor will be installed.
So what am I missing here? Sure could use some ideas or thoughts.
Added info- this is a 1952 CJ3A with the standard L-134 engine. I have owned since this past spring. The engine has been in the Jeep since 1955 at least, probably the original engine. I have no history of any kind on this Jeep.[reason]Add info[/reason]