Okay, three more running and now back to my nemesis. It's been awhile since I've post on this. 1969 Mercury 220E with Kiekhaefer engine and MD147A Tillotson carb. Today, I finally inspected the reed cage. All valves looked great. So...
1) 120 PSI both cylinders
2) spark plugs good and spark on both sides
3) fuel line clean, intact, without kinks (I'll admit, I found the filter on backwards. This didn't fix the problem)
4) carb gone through multiple times, but most thoroughly the other day. Found residue on needle and an inlet. This did not fix the problem.
5) Kind of looked at timing at one point, but his has a form of CDI. Pretty simple and the machine idles smoothly. No back fire, etc.
6) Exhaust does not appear blocked
7) checked primer ports - both tightly capped/ sealed, not in use.
Today while it was running, I sprayed starter fluid in the carb. No change in RPM.
So, I've been assuming a fuel delivery issue. However, it's all about air:fuel ratio and I think it's around 15:1. Is it possible that too much air is getting in? If too much air, kind of the same as not enough gas. Bad seals, cracked crank case, shot rings? The thing is, it starts easy, idles nice, and when you open up the throttle it does nothing. It does not bog down and die.
My current thought: When I had the read cage off, got down close with a flashlight and turned the clutch, I could hear air leaking. Could it be a bad ring all along? Sounds like the MAG side.
Slow as it goes.