it's normal to lean in loops- do 4 to 5 in a row and see how the engine responds. no negatives- Clarence Lee from RCM also stated that. i run morgan's fuel to and it says the same thing. take your fuel jug and shake it. see it foam? now take and squirt some armorall in there and reshake. no foam right? i've been doing this for years and have had no problems. whenever i open a new jug of fuel, this gets done first thing. how many tanks of fuel (on the ground) have you run through it since you freshened it up?