Bad Gasoline symptoms in a 2-cycle?

[Tri-Motor]

I think I got some bad gas. I ran my YT125 pretty much empty, then bought some gas and filled the tank. It was running perfectly fine before I filled it up. Now after filling the tank it won't idle unless I turn the idle screw in a turn and a half, but then it idles to high. Also the RPMs occasionally won't drop when shifting like it has an air leak, but it was perfectly fine before filling the tank. I drained the gas and put some in a small jar and it smells like really strong alcohol and is really cloudy. Can bad gas cause a 2-cycle to run/act like this? I got the gas at Holiday. Thanks

[barnett468]

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if it is cloudy, the gas itself is crap, crap, crap . . 2 stroke oil will not make gas cloudy, it will only change the color . . simply put some new gas in and call us back if it still runs crappy . . drain that crappy gas from the carb also and install a new plug . . give that crap to someone you don't like and dont buy gas from that crappy station ever again.

[3WW Star-John_Neary]

@Tri-Motor - Make sure to clean out your carb float bowl and flush the fuel tank with a bottle of 99% rubbing alcohol.

[El Camexican]

I ran my YT125 pretty much empty

That's when crud (AKA particles) that accumulate at the bottom of the fuel tank and float bowl are most likely to make it into a jet and plug a hole. I'd pull the carb, clean it (specifically the pilot jet) and splice an inline fuel filter into your gas line if you don't already have one.

[onformula1]

Here's some tips & tricks I follow and have never had a fuel issue.

Buy fuel from a name brand company that has a station that is very busy.
Never run the tank out of fuel
Run a inline fuel filter
Clean your gas tank every other month, it's fast and easy to do
Don't use fuel that's been sitting around
Keep your carb clean
Use a funnel with a brass fine screen and keep it clean, I store my funnels in a sealed Tupperware tub.
Mix fresh pre-mix before you ride

[3WW Star-John_Neary]

couple more fuel tips

fuel lasts longer if you keep it in a metal can, plastic lets the good stuff in the fuel bleed out

store your fuel on top of wood and never on concrete, it will pull water right up through the concrete and into itself

fuel starts to go bad after 30 days no matter how well you store it, in your fuel tank with the open vent it starts going bad with in a week

if you suspect there is water in your fuel pour a half pint of 99% rubbing alcohol into your tank and it will keep it from beading up in carb bowl

[onformula1]

couple more fuel tips

fuel lasts longer if you keep it in a metal can, plastic lets the good stuff in the fuel bleed out

store your fuel on top of wood and never on concrete, it will pull water right up through the concrete and into itself

fuel starts to go bad after 30 days no matter how well you store it, in your fuel tank with the open vent it starts going bad with in a week

if you suspect there is water in your fuel pour a half pint of 99% rubbing alcohol into your tank and it will keep it from beading up in carb bowl

Man, I forgot one, thanks.

I store in a red steel GI gas cans, then mix in a plastic quick fill tank.

[yaegerb]

couple more fuel tips

fuel lasts longer if you keep it in a metal can, plastic lets the good stuff in the fuel bleed out

store your fuel on top of wood and never on concrete, it will pull water right up through the concrete and into itself

fuel starts to go bad after 30 days no matter how well you store it, in your fuel tank with the open vent it starts going bad with in a week

if you suspect there is water in your fuel pour a half pint of 99% rubbing alcohol into your tank and it will keep it from beading up in carb bowl

Never heard of the half pint of alcohol tip before. I assume you can run that through a tank of gas with no ill effects to the motor?

[3WW Star-John_Neary]

Yes it runs thru the bike just fine and will clean the ports a bit, when we raced Speedway we used a mixture of Trick racing fuel, Methanol and Klotz nitro and if we did not add in some 99% Isopropyl alcohol it would always have water in the fuel issues that became a jetting nightmare.

[El Camexican]

I didn't know about the concrete floor thing, I hate storing fuel. Menthol hydrate is fantastic for breaking water up and getting it to run through the system, but its hydroscopic, so if you don't run your tank almost dry you end up with even more water in your tank. We used it by the gallon up North.

Where can one find a galvanized steel fuel tank these days??? I spent time looking a few years back and the closest I got was a guy on ebay selling them out of China without a zinc finish. VP claims their fuel is good for a couple months in the drum after it's been opened. I know a lot of guys would let it sit over the winter and use it at the drags, but in a plastic drum it's junk in less than 2 months.

So on the topic of old fuel what's collective 3WW opinion on dumping left over pre-mix into a modern car tank to get rid of it? I typically try not to put more than 3 gallons into my truck at a time and only when I have at least a half tank of fuel to dilute it. I can only run so much through my 4 stroke lawnmower. It's never been run on straight gas

[barnett468]

So on the topic of old fuel what's collective 3WW opinion on dumping left over pre-mix into a modern car tank to get rid of it?

oh boy...an OIL thread!


Holy crap!

[El Camexican]

oh boy...an OIL thread!


Holy crap!

NO!!!!!!!!!!!!!!!!!!!!!!!!! It's an O2 sensor, catalytic converter question. I did NOT mention a brand or ratio, so keep it PG please!

[atc007]

Mine goes in old ,or new, tractors. They say it raises hell with sensors,,,but are they wrong? Sounds like you've proved them wrong already lol. Yes, gas,nor batteries like concrete. Wood is always best to store both on. And to the op, clean your carb,tank and petcock.. As said, crap from your tank got in your carb. It needs ALL orifices blown out thoroughly.

[Tri-Motor]

Thanks everybody. The gas that I put in the jar seperated out. I just drained the tank and carb and cleaned them out, then refilled it with 87 non ethanol and it's back to it's normal self. I put the old gas in my garden tractor and it runs fine on it. That old Briggs and Stratton (1948 Simplicity walk behind tractor) seem to run on anything that resembles gas

[barnett468]

Thanks everybody. The gas that I put in the jar seperated out. I just drained the tank and carb and cleaned them out, then refilled it with 87 non ethanol and it's back to it's normal self. I put the old gas in my garden tractor and it runs fine on it. That old Briggs and Stratton (1948 Simplicity walk behind tractor) seem to run on anything that resembles gas

all alcohol is highly hygroscopic . . this includes, methanol, ethanol, isoproplyl, denatured and grain alcohols etc.

all alcohol is also miscible with water

"miscible" is different than "soluble", and in this case, it means that no matter how much alcohol is added to water or vice versa, they will continue to mix and stay mixed and will never separate . . in other words, one will not settle to the bottom if left on a shelf for 50 years.

water is barely "soluble" with gas and it takes very little before the gas can no longer "absorb"/mix with it before any additional water will settle out.

its a bit like mixing sugar or salt with water . . if you add 1/4 teaspoon of either to a glass of water then stir it, the two will stay mixed for the most part, however, if you add 1/4 cup of either and stir it, maybe 95% of it will not mix with it and will settle to the bottom of the glass within a few minutes.

since the water is miscible with the alcohol but not with the gasoline, nor is it soluble with the gasoline to a significant degree, it mixes with the alcohol but not the gas, and the water then forces the alcohol to separate from the gasoline . . again, kinda weird.

basically, if corn gas was kept in a sealed container with no airspace where it could not get any condensation inside, the alcohol would never really separate from it.


the amount of moisture/water that alcohol can wick from the air is limited . . this means that after the alcohol is diluted with enough water, it is basically no longer hygroscopic, but if more water is added, it will mix with it . . its kinda odd.

its claimed that at 70 degrees, gasoline can mix with 1 1/2 tablespoons of water . . i have never done this exact test but i gave done similar and have never seen this happen
alcohol barely mixes with gasoline wa