I run a pint per tank in my fuel injected truck. That’s about double the dosage on the bottle. Never hurt anything, and I picked up some mpg.
I also use it in my lincoln sa 200 welder, which has acarburated flat head four cylinder. One pint to 10 gallons to cushoin the valves instead of leaded gas and to clean up years of carbon deposits. It runs great. The fuel is actually red in the sight glass! No ill effects.
The only thing I have found is that if u use way too much it will smoke a little, but unless you have catalytic converters it won’t hurt. If you do have cats you might wanna be conservative like I am with my truck.