Honestly its gas tank gunk.(old, bad/varnish gas) Now most will replace the tank I took a chance went for it and got to deal with the aftermath. Now it runs fine. I told the wife "the car sat for years the first time I had it in the road, i didnt replace the tank then..." I may replace the tank yet but i dint want to stop what i was doing which was to get the car running, but not on a gas can like it was.:) I know being cheap but I survived. Now one thing I also had done is put a heat spacer between the carb and intake, i suspect the gas was flashing off between starts. I had to long crank after hot shutdown before it would start.