Been working on this saw for a few days and wanted to share something that may be helpful to someone else in the future.
Finished rebuilding with new bearings, seals, and rings and was ready to see how she would run. It fired off after a few pulls with the choke, so I was optimistic all was well. Started up with choke off, but didn't seem to be idling well. Tried richer, then leaner on the lo side, but still didn't seem right. When it would sorta hold idle, as soon as I gave some throttle, it would bog out. Noticed extra fuel coming out of the carb, so figured something wasn't right.
Took the carb off, checked that the gaskets were on the right side of the diaphragms, needle not stuck, etc. Everything looked normal. Put it back on, tried again, and same thing. These HL 273s have a governor, so started thinking maybe it was failing and letting too much fuel pass prematurely. Took an aluminum pie plate and punched a plug to eliminate the governor. No luck, same bad running.
Looked at the reeds to make sure they were seated correctly. Everything looked as it should. Decided to do another vac/pressure test. I'd tested it during assembly, but thought it wouldn't hurt to check again. Sure enough, no leaks for vacuum or pressure.
Decided to swap carbs with another good running 2100. The carb from the other saw behaved the same on this one, and the carb from this one ran great on the other 2100, so I knew it wasn't a carb problem.
So, good carb, no air leaks, plenty of compression, runs at idle, but a bit rough, and won't take throttle..... what could be going one here. Decided to look at the ignition system since I'm running out of possibilities.
The point gap was good, all was clean, coil impedance appeared good using a meter. Removed the condenser to check it once again. It was a hair over 0.2 uf when installed which seemed good. I noticed when I removed it the wire was a bit loose and would rotate. After handling a bit, this is what happened.
Turns out the wire was barely holding on by a few strands. It measured good capacitance, but wasn't capable of handling current flow. Replaced with a new once, and sure enough, now it runs great.
I never dealt with a bad capacitor before, so this was a learning experience. Always figured if bad, there wouldn't be any spark, or it'd be too weak to even run. This thing had a good enough looking spark at the plug with this bad condenser installed, and even held a rough idle, but wouldn't open up, flooding out instead. The condenser was the last thing I thought of. Learn something new everyday.
Dan