Oh and an admission of guilt.
I had siphoned one 5 gallon can out of the old tank before replacement.
I then purchased another can and put new fuel in it to put in the new tank.
A few hours ago I put about 2.5 gallons in the new tank just to fire it up (with existing carb) and check for leaks.
When I put the can back in the garage I realized I used the siphoned gas from the old tank! Not the new gas I bough specifically for this purpose!
These are the things I do... STUPID!
I only hope that the siphoned gas was "off the top" and didn't contain any crud.
GRRR.