Best Additive for 2 cycle gas?

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Hi everyone,

I have a question. What is the best additive for 2 cycle gas? I have a Stihl chainsaw and string trimer. They are about ten years old. I have been using Stihl 2 cycle oil and 89 octane gas. Have not had any major trouble up until now, they both started when I went to use them. Then, this last tank of gas, I went to use the trimer and I couldn't get it started. I don't if it is bad gas or maybe ethanol in the gas finally caused issues?

I know using ethanol free is better for the 2 cycle equipment, the problem is, the closest station that has it is about an hour away.

What can I do to get the trimer running again? And if I can get it running, is there an additive I can use to clean things up?

I noticed in the last couple of years, there is a number of additives that are now on the shelves to treat ethanol gas. What is the best way to avoid issues like this (not starting) going forward?

Thanks,
 
Dump the crummy gas out of it and re-fill with fresh gas. Prime it well. See if it will start.

We have ethanol free gas here in Angola. It's called "Recreational Gas"...because the boaters want it. I use that and the Stihl synthetic 2T oil. It's already got fuel stabilizer in it. I've never had a problem.

If fresh gas and oil doesn't work...if it was me, I'd put a healthy dose of Berryman B12 in the fuel and try to clean up the carb with that.
 
Home Depot has 2 cycle fuel that is ethanol free. Give the carb a good cleaning, replace the fuel lines, fuel filter, air filter and spark plug. Good luck
 
VPracing SEF you can not fix problems of ethanol gas if it contains it. Engineered fuel is your best bet if small use or any use or at least shut unit down and store with engineered fuel.
 
I am Mr. Two Stroke, if I can get it in two stroke I do. Since I started using SeaFoam mixed per their instructions on the can to stabilize the gas, I have had zero problems and some stuff sits over a YEAR.
Three lawnboys, Echo trimmer and Homelight and echo blower plus countless two stoke ATVs and motorcycles. SeaFoam works, Stabil let me down, the red stuff anyway. Never tried the Blue Marine stuff.
I've heard good stuff about Startron but I am not really having issues since I started SeaFoam so I can't comment if its better or not.
 
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BTW my last Craftsman Weed trimmer two stoke lasted over 20 years and still ran good but was getting hard to start so my wife bought me a brand new Echo trimmer for Christmas. No engine issues with it in over 20 years of running it. 23 years to be exact.
 
Originally Posted By: Phishin
Dump the crummy gas out of it and re-fill with fresh gas. Prime it well. See if it will start.

We have ethanol free gas here in Angola. It's called "Recreational Gas"...because the boaters want it. I use that and the Stihl synthetic 2T oil. It's already got fuel stabilizer in it. I've never had a problem.

If fresh gas and oil doesn't work...if it was me, I'd put a healthy dose of Berryman B12 in the fuel and try to clean up the carb with that.


A cousin of mine gave me an old 2 cycle Weed Eater string trimmer . The little plastic fuel lines had gotten brittle and started breaking . I replaced the lines , mixed up some 100% unleaded & 2 cycle oil . Had to pour a little fuel into the carb to get it to start . Got it running , but not well .

Couple of days latter , bought some B12 Chemtool and put a little in the tank . Seems to help it , running OK . During this , the primer bulb split & started leaking . Hot that on order , from ebay .

So , yes , try a little B12 Chemtool .
 
By the way , any small engine , last time you use it for the season , run it dry .

My SOP when I get ready to start a computer , next season , is new gas or gas / oil mix . Change the oil on 4 cycle engines . Replace the spark plug & air filter , if it needs it .

Wyr
God bless
 
I am a little scared of the B12. I d use it very moderately. It dissolves plastic. I only cleaned carbs with it and very little will stand up against this stuff but if put it in plastic measuring cup, it starts to cloud it and soften it big time.
It's usually my last resort, take apart carb cleaner, especially in small, lots of plastic parts motors. This stuff is probably the most potent varnish remover I know of.
 
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I buy Mercury or Yamaha 2-cycle oil, but if I'm in the Chain Saw shop I'll buy what they're selling as long as I don't fall over at the price.

Gasoline gets eaten by bacteria (if it smells bad, it's bug [censored] you're smelling) so it's perishable and won't last long (a year is "long"). Fresh fuel usually clears that up.
 
I met a man at a flea market with a trailer full of string trimmers and chain saws an leaf blowers. All were 2 stroke. I asked him where he got them all and he told me that he picked them up out of other peoples trash. Asked him if they were hard to get working and he told me that he just drains all the old gas first. He then adds a 1/4th cup of seafoam and fills the rest of the tank with good 2 stroke 30:1 gas. So I had an old weadeater leaf blower that I got after my Dad passed. I know that it had been sitting at least 12 years. Son had put gas in it to see if it would run. He pulled it a lot with no results. I emptied out that gas and then put in the seafoam. Pulled the rope 2 times and primed it with it first and then added the gas. Started on the second pull and ran all day. Had to refill tank once and still started right back up. I am a believer in seafoam.
 
I use ethanol free gas so I don't use an additive. But if I did, I would use Sea Foam or Stabil. I've heard good things about both. The ethanol free gas can get expensive. Regular gas is fine by itself if you don't leave it in for long periods when not in use.
 
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The past 2-3 years I have added MMO to my small engine gas and the gum/varnish problems have gone away. My POS string trimmer runs on Super-Tech oil (40:1) and I use 1 Tablespoon each of MMO and 2-stroke oil in 1-1/2 gallons of pump gas (10% ethanol). Startron also helps with water dropout, 2 teaspoons added to the fuel mix above. This has saved me a lot of problems as compared to just plain gas and its not expensive to add to fuel.. I know you guys hate MMO but it works for me and its cheap!
 
if u cant get it to run check the fuel line inside the tank is not cracked or leaking. I have seen the pickup line dissolve from the ethenol. replaced the line and all is good.
 
Enzyme Fuel Additive:

I ran a test about two years ago on an enzyme fuel additive and mixed it with various other fuel additives to see what effects it might have.

The result: don't mix it with anything else and here is why: The proteins in enzymes are usually globular. The intra- and intermolecular bonds hold proteins in their secondary and tertiary structures.

My results showed globular clusters of "something" that formed and settled and no solvent I had would break up these globular clusters.

I don't know what they are using for this "enzymatic" additive but I really have my doubts as to its efficacy.
 
I use the good Stihl branded 2 stroke oil and our stuff (few trimmers and saws) always starts good even with months old gas in them. So I'm guessing there is something in the oil to help. Someone mentioned "running them dry" at the end of the season...uh...that fuel is the only lubricant that engine has....so having it spinning with less than or no fuel in it is pretty dumb. Just drain the fuel out if you really think it's an issue over the winter. The most important thing....keep the fuel CLEAN. It doesn't take much debris to clog up a tiny carb.
 
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