I accidently put about 2 gallons of 2 stroke oil and gas mixed 50:1 in my ’99 GMC, the gas tank on the truck was almost full, will it hurt the truck to run this amount in it, I would think not but thought I would ask to make sure.

Also I use this truck very little, most for plowing and only put maybe 1k miles a year on it.

 

No it'll be fine.

My grandfather always dumps the old 50:1 in the vehicles

 

Thanks, ran it it seems to be ok. How much of that ratio do you think would be safe to put in a 20 gal tank?, never thought it would be a good idea to do that but seems quite a few have mentioned that and it would be a good idea since the 2 stroke oil is setting all winter.