Small Engines (Lawn Mowers, etc.): Regular gas ran in my Stihl eguipment., fuel stabilizer, stihl fs250

Question
Nathan,

I am about to go balistic because my son and his friend just used my Stihl 4mix 110R and my Stihl FS250 to mow a bank and ran regular gas in them for 30 mins.Their was about 1/4 of a tank of mixed gas already in them and they added regular gas. Do not even ask why they did this!! I am worried that they have caused damage.I have drained the remaining fuel from them but I need to know your thoughts on damage and if I need to run anything like fuel stabilizer through them?

Answer
Hello Tim:

Sorry for the Delay. This Question was Located in the Question Pool. If the Units are Still Running Properly, then Increase the Oil to Gas Ratio for a Couple of Tanks and the Engines Should be Fine. They will Smoke More than Usual, but you Need to Build the Oil Film Back on the Internal Components. You are Lucky the Tanks had Fuel Mix in them when the Regular Gas was Added. At Least the Engines were Not Run Without Any Oil at All. That is the Only thing that Saved the Engines and Prevented them from Locking Up within a Couple Minutes of Operation. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 9pm EST (US). My New Day Starts then. Thanks.

Respectfully

John