Old Gas - how old is too old
 

In the past year I have not had time to work on my car. Right now i'm trying to get her started after a rebuild. I'm having a hard time getting her started so I'm trying to find things that may have an effect on hardstart.

The gas (w/ 2 cycle oil) has been sitting for about a year now. Should I replace it? throw some octane booster in there? Should I not worry?

How old is too old?

TIA

Some say that low-grade gas will start to deteriorate after 2/3 months, while high grade may start after 4/5 months. I've never had a problem with cars starting even though they have sat for over a year. If the fuel has E10, it will also deteriorate faster. The only problem I ever had was with a garden tractor years ago. As I don't drain the fuel in winter, it started fine the next spring, but wouldn't run under a load. Changed gas, no problem.

Not a very definitive answer, but if you don't have much fuel in the tank, it may be wise to drain and refill, then that will be eliminated. You can always try a little either, or starting fluid in the intake to see if the motor will catch.

I may have to lay claim to using the oldest gas!

Recently took my 1980 out of the barn where it had been sitting for at least 11 years. Pulled plugs, lubed rotors, spun motor over, replaced plugs. Removed carb & did a quick rebuild, put that thing back on and the silly car fired up. Since it had a full tank of gas (but no stabilizer) I actually ran it out before refilling with fresh fuel. This car has a RX4 four port 13B, RB Holley & exhaust plus a Big Street Port amongst other mods.

Amazed me that the thing ran at all - much less ran well on that ancient gas. Sort of prooves the point that rotomotors will run on about anything.

Henry Payne
HPMotors
Pelzer, SC

That poor car. :)

If it smells funny, its probably bad.

If it smells alot it's bad. The fumes/gas vapors is what the engine runs on and after time they release from the liquid. If too much gets separated from the liquid then the gas won't burn right. But then again it depends on what brand/quality of gas you have because certain companys put certain amounts of detergents and what not into the gasoline that helps preserve it...I think...Thank god for EVAP! :)

If it was running well on the old gas, what problems could it have caused?

On the upside, she got 5 gallons of 110 octane leaded race gas on the first refill :) Then it was REALLY cleaned & waxed - so after all those years in storage its back on the road.

HPMotors
1980 LS w/4 port 13B, LSD, rear disks

I know its hard to describe the smell, but can you describe it? :)

You are spot on in trying to describe an odor, but try this.

Know how fresh gas smells? Sharp odor? Old gas is different, seems "dull" and just stinks in a bad way. Once you smell the old gas you will never confuse it with fresh stuff.

old gas smells nothing like new gas. it smells like ass

Bingo..

If its bad you will KNOW it..

Bad gas smells like varnish/turpentine and what the Mouse said above. Then again, I wouldn't really know because I havn't had to *kiss ass* like J-Rat has had to, to get thru life (sorry man, I couldn't let a chance like that slip by). humor

It can cause nasty gum deposits and varnish. It really doesnt burn right.

But yeh, RX-7s can run on very, very bad gas.

I've started RX-7s that have been sitting for a decade as well and run them as you described, they're just a little harder to start :P

But everyone should definitely try to avoid using gas older then half a year if it can be avoided.