I would start by checking the filter between the tank and regulator/if that is clean try (after warming up the unit)to drain the regulator this is done by removing the 12 mm bolt located on bottom of regulator put rags under it because there will be fluid and pressure you don't want to loose the nut/next check the injector this is located to the right of the carb and a little down(it will have a supply line going to the regulator)try cleaning with carb cleaner/did you pull the supply line off the mixer and crank the motor?if the regulator is bad you will get liquid and vapor or just straight liquid(I have put new ones on and found some times I got bad ones from the factory