Well......I spent an hour with it in a more relaxed and paicient
state of mind instead of trying to find a "pit stop" solution.

As a test I managed to install a piece of 5/8 ID hose in place of the 1/2" OD copper tube between the reg and "carb".

No difference in symtoms.....still goes lean after 20-30 seconds.


Here's the progress part:
I do now KNOW for certain it is going lean as I was able to help it by choking down the air inlet -carefully- and more precisely with my hand and actually keep it running.

The possible culprit:

In this process I have also found I can "play" with the primer button on the Model J and advert stalling altogether!
Matter of fact, after a short learning curve (lol) I found if I play the primer button in sync with the throttle, I can go from idle to wide open with no lean out.

And it seems if I just hold the primer button in with little force from my finger, the whole program seems to improve over the entire no load speed range.

Whe I leave the button alone, again, it will idle for 20-or-so seconds and then 'go lean'.

This Model J regulator has sat in a drawer for aprox. 25 years and was never used.
Is it possible time and age has damaged the internal rubber parts? There were no plugs in the ports, they did look clean, but I suppose it may have dust in it.......

I guess the next step is to do the pressure test and probably disassemble it for inspection.


Oh.......also had a timming light hooked up to the coil wire all the while, and it did seemed to be a steady output with no misses or shut offs.