When is "old gas" too old to use?

[jamesqf]

Back during the first oil embargo, I was working on a ranch with a fairly large "junkyard". Whenever the owner bought a new something, he'd just drive or haul the old one out to the field back of the barn & park it. (Scored a repairable Sunbeam Alpine and one of the first Toyota pickups in this country from there :-)) So when the local station was out of gas, we'd go out with buckets and drain the tanks of the old cars & trucks. Seemed to run fine.

I think the issue with small engines & such is not really the gas itself, but the varnish & crud that builds up in the system from the gas just sitting there. But if you put that same gas in a different engine, it does ok.

[silverinsight2]

I stored a Honda Insight for 2 1/2 years, with Sta Bil in the tank. I had the engine run about 9 times in that period.

No problems on startup.

[Ryland]

Originally Posted by jamesqf

I think the issue with small engines & such is not really the gas itself, but the varnish & crud that builds up in the system from the gas just sitting there. But if you put that same gas in a different engine, it does ok.

I've had gas that was just over a year old sitting in a gas can not work in a lawn mower so my family has taken to tagging and dating gas cans when they get filled so we don't end up with gas that is years old.

[jamesqf]

Originally Posted by Ryland

I've had gas that was just over a year old sitting in a gas can not work in a lawn mower...

Yet another reason I'm glad I bought an electric mower :-)

[Thymeclock]

Originally Posted by Ryland

I've had gas that was just over a year old sitting in a gas can not work in a lawn mower so my family has taken to tagging and dating gas cans when they get filled so we don't end up with gas that is years old.

It's not the gas. As I mentioned, I have some stored gas that is older than that, and it works fine.

What probably occurred is that you left enough gas in the tank and/or the carb (over winter) for it to create residue and clog the carb. Also, if the machine is getting older, it might have been due for a carb clean out anyway, and it was coincidence that the carb happened to poop out when you put gas in it.

[Ryland]

Originally Posted by Thymeclock

What probably occurred is that you left enough gas in the tank and/or the carb (over winter) for it to create residue and clog the carb. Also, if the machine is getting older, it might have been due for a carb clean out anyway, and it was coincidence that the carb happened to poop out when you put gas in it.

I tend to either run my snow blower and motorcycle out of gas before storage or drain it out the drain plug in the bottom of the carb, I've also put old gas in a small engine that had been running up to that point and had it smoke and stall and found the fix to be as easy as fresh gas, I've had that happen enough times that asking how old the gas in the tank is, tends to be one of my first questions when fixing a small engine.

[jkv357]

I always add Stabil to every can when getting gas for my small engines, as I don't go through it that fast. Always make sure the can is tightly closed as well.

I've recently found Regular gas without Ethanol that I use in the cycle and small engines.

I also drain the gas from the small engines, run them dry, and change oil before storing every year. They always fire up immediately when needed.

As it gets colder I make sure to use up all of the summer gas that I have sitting around. If you happen to have a small generator, be sure to swap the gas regularly from summer to winter (and back) every year and run it - before you need it

Simple stuff that saves problems and headaches later.

[beatr911]

So, it sounds like small, carbureted motors generally tend to not do as well as larger FI motors on old gas.

How old is too old? It depends. If it runs bad it's too old.

My experience is that winter fuel goes bad faster than summer fuel. E10 goes bad faster than straight gas. Mixing some new fuel with old/bad fuel can get the batch to a useable state, better to use old fuel than use it as a grease solvent, weed killer or fire starter.

[NeilBlanchard]

If it is unsealed, then eventually you will get a gummy/shellac-like crust that has to be scraped out. I bought a 1976 Yamaha XS-650 back in ~1983 and the float valves were stuck and wouldn't let any gas into the carbs. I had to manually scrape out the gunk that was left inside.

[jkv357]

If what I've heard is true, the new gas is even worse.

I saw a new (at the time) Honda Valkyrie 6 cyl with 200 mi on it in the service dept at the dealer with the carbs pulled. Turns out they prepped it and then stored it in the warehouse for a couple of months. In that time the carbs were gummed-up enough that they had to be removed and cleaned.

I regularly use Stabil in my gas, but Seafoam also claims to be a stabilizer. I've used Seafoam as a fuel system cleaner, but not as a stabilizer. As a rule, after running my "storage gas" through the cycle I will use a fuel system cleaner on the next tank. I like Techron Concentrate or Seafoam (1 oz per gal), and not the cheap-o "fuel injector cleaners".