True or false... old 2-stroke gas can damage/blow a 2-stroke motor

[rechargeable]

A landscaper friend of mine related a story to me recently of a guy he knows who blew up a few of his chainsaws by running old fuel in them. After hearing that, I've become fearful of using my blower and chainsaw after a couple months of them sitting there with fuel in them.

Any input on the veracity of this old fuel fear?

[LouisianaLawnboy]

Ya that's true. Don't know about the engine part, but it will definetely mess up the carb.
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[LushGreenLawn]

Really, its the old fuel sitting in the machines that cause problems. Even if you dump out the old fuel, and then run the machine with new fuel, the damage is done.

In the past I would say not to even sweat a couple of months, but with all the ethanol on these new fuels, we are seeing problems even when they don't sit between uses. Its really bad for our small engines.

[whosedog]

My small engine shop told me to put Sta-bil in the gas if it sits even more than a few weeks.He adds it to his outboard motor tanks when he stores them for the winter, but once the gas goes bad he said get rid of it.

[ecko]

My old 80's Stihl 076AV saw sat for over a year, may have even been two, with gas in the tank with stabilizer. Fired right up, but didn't run too good. Dumped out the old gas, put in some new gas, and it runs great. I'm not saying you should do this or whatever, I really should have ran it dry before letting it sit, but I'm just sharing a personal experience. :)

[rechargeable]

Hmmm, well, I've dumped the gas out of my machines but a little is obviously still sitting there in the carbs. I gather there's no way to get that out of there without running them a tiny bit with some fresh gas in the tanks? One saw and my blower have primer bulbs, so I guess I could sit there with the throttle open and the air filter off and just prime it all out the intake? But then there's my Stihl saw which has no primer bulb...

[LushGreenLawn]

My small engine shop told me to put Sta-bil in the gas if it sits even more than a few weeks.He adds it to his outboard motor tanks when he stores them for the winter, but once the gas goes bad he said get rid of it.

even for a few weeks? It sounds like your dealer wanted to sell some Stabil!

[whosedog]

You could be right lushgreenlawns but I bypass him and get it at walmart much cheaper ,dealers markup is too high. I only add it to the big tanks end of season , small equipment I add ,run engine to get it in carb, drain tank and run dry.I figure that way if theirs a small amount left somewhere at least it's treated.I think actually the manual says to put a small amount of oil in the cylinder for storage but I never do.

[Breezmister]

.

Any input on the veracity of this old fuel fear?

A good quality 2 cycle mix has fuel stabilizers all ready in it.

But on the other hand, went I did store any gas powered equipment, I all ways put Sta-Bil in the fuel, started it up and ran it for a few minutes to get into the carb, fuel lines etc. Shut it off and that is it. I did not drain the fuel out of the tank.

Come the spring, fuel would be dumped in to a can and fresh fuel added, the old fuel would go into a truck :rolleyes:
Never had a problem to date with a carb I treated....
........and the truck ran fine :laugh:

[44DCNF]

Hmmm, well, I've dumped the gas out of my machines but a little is obviously still sitting there in the carbs. I gather there's no way to get that out of there without running them a tiny bit with some fresh gas in the tanks? One saw and my blower have primer bulbs, so I guess I could sit there with the throttle open and the air filter off and just prime it all out the intake? But then there's my Stihl saw which has no primer bulb...

If you are talking about for storage, dump the tank out, then start and idle the engine until it dies to burn the last bit out of the tank, line, and carb. Prime a few times and restart it. It will refire and use up what you prime into the intake. What little is then left to evaporate should not leave enough residue to cause any trouble.

If you are talking about just getting rid of the old gas in the primer when you add new, all you need to do is prime and start it. That will flush the lines and primer out with fresh gas.

[dutch1]

From what little research I've done on fuel stabilizers, my opinion(for what thats worth) is that it's a waste of time and money to add stabilizer to old fuel. Most fuel stabilizers are antioxidants/amino acids that serve to put a wrap around each fuel molecule to isolate it from being degraded by oxygen. What is "old fuel"? Most information I've seen indicates that fuel starts to degrade in 30 days or less depending on where and how it's stored. If the can is in the sun the heat only serves to hasten the action.

Personally, I add stabilizer to every empty container before I go to pick up fuel at the station. The same was true when I worked in a shop envoirnment. Since most of todays fuels contain alcohol(which contains carbon, oxygen and hydrogen atoms) I wonder how much good the stabilizer actually helps. I guess I'm a creature of habit so until I learn differently I'll probably continue to use it.

Dutch

[Breezmister]

Most fuel stabilizers are antioxidants/amino acids that serve to put a wrap around each fuel molecule to isolate it from being degraded by oxygen.

Very very interesting (my best Artie Johnson impression)

Many many years back, I had a chat with a Tanaka Tech about a fuel problem I was having with a trimmer, anyway we got talking about fuel stabilizers, and I wish I could remember what he said, But I do remember him telling me that one of the things that they do is raise the octane level a few points, like going from 97 to 101......

any one else ?

[echoman8]

If you are talking about for storage, dump the tank out, then start and idle the engine until it dies to burn the last bit out of the tank, line, and carb. Prime a few times and restart it. It will refire and use up what you prime into the intake. What little is then left to evaporate should not leave enough residue to cause any trouble.

If you are talking about just getting rid of the old gas in the primer when you add new, all you need to do is prime and start it. That will flush the lines and primer out with fresh gas.





Right on with 44

Regardless of the fuel and oil, you need only empty the tank and run the fuel out of the carb and lines. This will protect any 2 cycle engine from the fuel in it. This is OLD TECH.

Practically all "primer bulbs" are actually "purge pumps". They only put fuel in the carb rather than in the "ventura" (cavity in the carb) and all excess is returned to the fuel tank. There is no need to worry about the bulb and the fuel in it.

There are many more worries to worry about for our modern fuel and the 2 cycle engine.



echoman

[dutch1]

Breezmeister,

I've never heard of anything to that effect and would not care to argue one way or the other. I may not remember correctly of the quantity, but I believe that the rrecommended rate on my Briggs/Stratton fuel stabilizer is 2.5 ounces per 5 gallons. I've never checked for the flammability level of the stabilizer but it would have to be decently high in octane to raise the level in 640 ounces of gasoline that much. Wouldn't say it couldn't happen, but it seems unlikely.

Dutch