Fuel additives

I have not been as diligent as I should have in regularly starting my 1979 Airstream motorhome that has a rebuilt Chev 454 gas engine. Needless to say, the battery died and it has been approximately 10 months since it’s been run. I did not put any gas additives in the fuel tanks. Is it safe to start the engine with old gas or do I need to drain the tanks of the old fuel and add new gas before I start it?

It will not do you much good to replace the fuel in your tank. The problem, if any, is the fuel that has been left in the carburetor. It may have gummed up the works.

My experience with carburetor cars that have sat for a long time is that they are, in most cases, good to go. I recommend you just go ahead and try to start. You may have quick success. If so, just drive. No need to worry at all about the remaining fuel.

If you have starting problems, that’s another matter. Let us know.

I agree with SteveF that the fuel in the carburetor will likely give you the biggest headache, but after 10 months with no fuel stabilizer, I would probably drain the tank, depending on how much fuel is in there. If there isn’t much fuel in there, you can fill the tank and have mostly new fuel in the tank without draining.

I think I would start by servicing/replacing the battery as needed, then I would try it out. You may get lucky. Under those conditions it is quite possible that will do it. If not, you are not likely any the worse for trying.

I would not push it any further, (that is driving it a hundred miles now) and then putting it back into storage with the same old fuel.

The gas is only ten months old, not ten years. Start it and DRIVE it, as opposed to just letting it run.

If you can’t drive it enough to use up the old gas, drain it and refill with fresh gas and fuel stabilizer, which will help preserve the gas.

I’d probably dump a can of Seafoam into it (saving a couple of tablespoons or so to dump down the carb), then 5 gallons of fresh gasoline - and then give it a go.

Get a ‘battery tender’ or other small automatic battery charger and charge overnight once a month or so.

The gas shouldn’t be any problem. My motorcycle sat unstarted from Oct. 2010-May 2011 with gas in it and no stabilizer and it started and ran fine. Motorcycle carburetors are much more sensitive to such problems than most automotive carburetors.

Fill with fresh gas and start it or start it and fill it with fresh gas and add stabilizer if its going to sit

I doubt you will have any problems getting this vehicle to start and run. It’s only been sitting for ten months. I once acquired an old Chevy truck with a 350 and Quadrajet that sat for over four years. I decided to just stick a battery in it and see if it would start, and it did. It didn’t run too well on that old gas, but it did run. I would suggest just firing it up, driving it for a while, and fill it up and add fuel stabilizer for good measure. Then make an effort to give it a good drive every few months.