2 oz per gallon full time in the tank should keep it clean. We have a 6.5 HP China knock off honda engine and an 18 HP B&S that if i will get them hot and add pure Seafoam as the last oz of gas is leaving the tank then go to full choke when they start to die they will run on pure Seafoam until the cows come home or the Seafoam runs out.
On the 10 year old 4000 Onan RV generator that had .2 hours showing when we started working with it for a neighbor we got it stated by spraying carb cleaner on the intake air filter. Then we removed the gas line and dumped it into a 5 gallon gas jug and added a line to the carb fuel intake connection and inserted a small funnel and ran it on pure Seafoam using a small shot of Carb cleaner spray over and over to keep it running until it warmed up some then letting it die with only Seafoam in the carb and intake system.
That helped a lot and we did that again Monday and giving the pure Seafoam until tomorrow evening to see if it will run smooth with roof AC running. It was much improved after the first treatment. I hate tearing down a carb on a never used generator that I do not own. :)
