1973 Series III Land Rover 2.25 Petrol, won't run

[ldmpiv]

I come to you all seeking knowledge, because I am at wits end on this engine. Let me take you on a story, last year 2023 september, I serviced the engine on my series III, new distributor cap, leads, points, plugs, and coil. Everything went well, engine ran great, then I had some leaks from my front and rear diffs so I let the car sit for a couple of months, I would start it occasionally and move it around, with no issues. Spring of this year, I go to move it and it is running rough, like pops and bangs and back firing. I move it where I need and shut it off, next day I go out and engine will turn over, but no combustion. I go through the entire engine checking timing, lifter spacing, checktiming, and readjust the points. Boom I get some combustion, but it still runs rough. I table it for another few months and here we are end of December 2024 and I don't even get combustion. I have replaced the fuel, I have replaced all of the original parts on the engine from the service back in September. I will get one cylinder to pop occasionally, but nothing else. I have spark at the points (it seems dimmer after the first few turns). I have spark at the plugs (maybe weaker than what I would think, but spark non the less). We have checked compression averaged in the 140s, I had one cylinder at 130. I am getting fuel to the carb. I don't know what else to check. Again, I can get one pop from the engine maybe every 30 seconds of cranking. I just don't understand how I can go from a running engine to this mess, with seemingly nothing changing.

[jimrr]

how old is the gas? I can't believe you checked the valve clearance, wow ! this is a simple diagnosis, keep writing.

[erik88lr]

You didn't list "condensor" among the earlier replaced parts. Could be that.

[roverp480]

Ditto - I have had these type of symptoms on various vehicles . In order of frequency, condenser ( Capacitor) failing, carb issues, such a blocked jets or stuck none return valves, spark plugs, leads or coil failures and extremely poor fuel ( about 6 times in 50 years)
Condenser failing can result in symptoms ranging from a slight misfire through severe coughing/backfiring to total none running even if showing a spark from a plug sitting outside the cylinder.

[jimrr]

"ran when parked" ............. pretty common and your rig wasn't parked that long........ put a timing light or something on the plug wires and crank it and see what the spark is like. No, your valves didn't "fall out of adjustment" nor much else.... i'd bet it's electrical or maybe some water condensed in the fuel?