Ray and Tom said it was the secondary ignition due to Paula’s comment about it being worse when it rained, and suggested a tune-up, a new rotor, cap, and plug wires. Seems reasonable. But I think this problem could also be something else instead. Paula said it was related to installing a new fuel tank. She also said while cranking she held the accelerator to the floor. Both are an indication it could be a fuel-mixture problem. Too lean or too rich can produce similar symptoms, a sort of put-put-put before it starts, and then even after it starts, it keeps put-put-putting for a while before calming down and running smoothly.
What do you think? Could this be a fuel problem? If the tune up and wires don’t help, I’d suggest Paula ask her mechanic to take a look at the fuel filter first. Then the carb. Maybe the fuel pump too.