Ron,
Thanks for jumping in on this somewhat esoteric project of mine, even if it's not rocket science. Here's what I've done:
- Fixed flooding fuel bowls.
- Rigged chokes for both carbs so that the jets lower all the way. BTW, new fuel pump.
- Brand-new battery.
- Jets screwed two-and-a-half turns down at first. When running, two turns gives the highest revs, but does not help starting. After running to good warm-up for final torqueing of head bolts, plugs were quite black, so I leaned out the mixture another two flats. That didn't help the starting either. Went back to 2.5 turns down.
- Timing set at 18° with test bulb, but when it wouldn't start, I just kept twisting the distributor till I got the most frequent chugging, locked it down at that point and then fluttered the throttle valve till the ever more frequent caughs turned into a genuine start.
- Once running and warmed up, timing light revealed weird advance of about 60° at 2400 rpm and wild fluctuations, which led me to a bad distributor conclusion. Pulled distributor, which turned out to be nice and tight - no shaft play - but did have a badly fitting rotor and a pretty tight point gap. Switched rotor and re-gapped to .016. I also checked the distributor drive to make sure it was correctly positioned. Since then I've been unable to get a start, so I've not been able to re-check the timing with the timing light.
- I had initially adjusted the valves by the Volvo Manual method. After torqueing the head bolts, I adjusted them the sophisticated :-) Wilson/Hueppchen/Singher method. When I couldn't get a start that way, I went back to the old, Volvo method. At least, that way it started before.
- When I couldn't get a start with the original, armored cable coil, I exchanged it for one out of a 240. That was the one I had in when I got it to run, but that was coincidental. Now it doesn't start with the 240 coil either. What I haven't done is check the compression, but that wasn't anything to brag about before when, five years ago, I blew the rings on the two center pistons, trying to pass a semi doing eighty.

My conclusion: The electricals are pretty much as they should be, but the low compression, combined with the fact that there are only two cylinders attempting to fire, and that with relatively long time gap between them, just isn't enough incentive for the poor thing to get up and go. Rebuilding the engine is not an option for this purpose. I'd be better of getting that VW Diesel. It wouldn't have the Volvo charm, but, in compensation, I would be able to burn waste, fry-oil.

Sorry about the long story, Ron, but I've noticed that you like to have as much detail as possible before you give us the benefit of your advice, which in this case, as ever, is and will be much appreciated. I have the manifold off, but, in the hope you'll give me a good reason not to, I won't do any drilling till I've heard from you again.
Cheers,
Bob S.