Will doing this cause fuel gauge damage?

No.

 

If you don't drive the car a lot you want to fill the tank, not keep it half empty. Less chance of water vapour getting in.

Either way, you won't damage the fuel gauge or the fuel pump or anything else putting any amount of fuel in the car, just don't let it go completely empty and don't fill it completely with no air space. I don't think this is actually possible but people will surprise you with what they can do.

 

This is correct.

 

The gas starts to go bad after about 3 months. You can add a can of STABIL fuel stabilizer (or however much it takes for 6 gallons of gas) that will keep the gas "fresh" for about a year. I have a Subaru Outback that I haven't driven since early November (Ihave started and moved it monthly) and I recently took it in to be smogged and it passed with the 6 month old gas that was in it. So as long as you put gas in it every couple of months, you should be OK. And like David said, it is better to keep the tank full instead of half full.

 

Actually, these days fuel doesn't go bad for a very long time. STABIL contains alcohol, the active ingredient. Gasoline now contains about 10% ethyl alcohol. I've left fuel in cars for 6 months or more with no ill effects. Sometimes people will confuse water in the tank from condensation for "gas going bad from age".

Gas doesn't "gel" when it gets old either. It will smell different. It takes a long time to actually go bad enough to worry about. Over a year, usually. By then your 12V battery will be dead and the "traction battery" will be dangerously low.

 

but if i don't put stabil in my mower (off season about 5 months) it won't start in the spring and i have to remove and clean the carb.