Great to hear your on the mend. I had a heart attack about 5 years ago and I still have my days where I am tired and just have to slow down. Take it easy and don't push yourself too hard to start.
As for your
furnace, I would pull out the pilot burner and clean the jet really well. I had the same problem with my
ventura and the jet was very dirty and almost plugged. I ran a small strand of wire through it and it worked great. My furnace was a Coleman gravity feed and there was also an adjustment for the pilot
light flame height on the control valve. It was under a plug or screw(can't remember) but was marked. If the flame is too small, the main burner will blow it out or you will not get enough heat to the thermocouple.