Originally Posted by 67Elcamino
....A buddy of mine too out the gas tank and he stated that it had what seemed to be a blood red sealer like substance in the tank. He flushed it out and re-installed the tank.
Any idea what your buddy used to "flush it out"? If he used a solvent that dissolved the red stuff and then he didn't get all the solvent out that's no doubt the issue.
What I've done in the past is take the gas tank to a radiator shop and have it flushed and then evaluated.