i ran it for about 30 min, so the fuel should be ok now, i also had not changed the oil in a while so i also took the opportunity to change it as well.
there was about 20% water when i tested it, so it would have easily filled the bowl in the carby and therefore not worked no matter how much you pumped it
first time in 20 years i had picked up bad fuel for the mower and its hard to tell with the metal cans, so now on i will test a small sample in a clear bottle before spending hours trying to pull the motor apart
