Can you add too much stabilizer to gas?
Overusing fuel stabilizers is not necessarily bad until the fuel to stabilizer ratio becomes abnormal (like 1:1). However, adding too much fuel stabilizer doesn't have any benefit either. It will not extend the functional life of the gasoline anymore by using too much fuel stabilizer.
No it will not hurt anything. In fact if you were storing for longer than 12 months you can add twice the recommended dose at fill up and they claim it will keep your gas fresh for up to 24 months. One other thing, you really need to add the stabil at fill up as it will not improve gas that has already degraded.
Fuel stabilizers work in both 2- and 4-cycle engines. Best of all, using them is easy. Just add one ounce of fuel stabilizer per two gallons of fuel. This will keep the fuel protected and fresh for at least 12 months.
VERSATILE – STA-BIL Storage Fuel Stabilizer is safe for use in all gasoline engines, including 2-cycle. Use this fuel treatment in your vehicle, motorcycle, lawn mower, snow blower, boat, and generator.
“Stocking up on fuel isn't a good idea unless you are going to use it within a few months,” Ibbotson says. He says adding fuel stabilizer to the stored gasoline will help, but even that is not a cure-all over the long term.
WILL OVER-DOSAGE CAUSE ANY HARM? No, over-dosage is perfectly OK. However, we do not recommend adding more than 4 times the recommended amount. If more than 4 times has been added we recommend diluting the fuel.
What to do instead: Avoid risks with gas stabilizer. Manufacturers sometimes recommend draining the tank to winterize a lawn mower because the worst thing you can do is leave old fuel in an engine during long periods of storage.
On a long enough timeline — usually three to six months, depending on the quality of the gasoline, but sometimes quicker — the oxidation process will start to degrade gasoline to the point where it becomes a soupy, varnish-like mess that can clog your fuel lines and gum up your tank, pump and injectors.
For STA-BIL® Storage, use one ounce (30mL) to 2½ gallons (9.5L) of gasoline, gas/oil mixtures, or ethanol blends. For STA-BIL 360° Protection, for storage and everyday ethanol treatment use one ounce (30mL) to 5 gallons (19 L) of gasoline, gas/oil mixtures, or ethanol blends.
Fuel-stabilized gasoline keeps for one to three years.
Depending on the product, the stabilizer can increase gasoline shelf life to between one and three years.
Which is better seafoam or STA-BIL?
Is Sea Foam better than Stabil? Both Sea Foam and Stabil Storage can keep fuel in good condition for up to 24 months. However, Stabil Storage costs half as much as Seafoam and is 2.5 times more potent, so it provides a much better deal overall.
Can you use too much Techron? A: Good to hear your car is running better using the Techron. Fact is, you can use too much Techron and cause damage to your fuel tank lining.

Gas treatments can be an effective way to maintain your older car, improving performance and potentially gas mileage. Further, antifreeze treatments can help prevent your car from freezing (and possibly stranding you at home until the temperature rises).