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How long for gas to turn to varnish?

31K views 17 replies 15 participants last post by  sthorp 
#1 ·
How long does it take for gas left in a gas tank, carberator etc to turn into varnish? Is it solid or liquid or pudding? Once its varnish, how do I get it out? I've got a '93 Honda Shadow VT1100 (my first ride) that has been sitting since I bought my FXSTBI a year and a half ago. I did ride it once about a year ago when I moved to my current place. I want to clean it up and sell it, but am worried that the gas has turned to varnish. Thanks for any help...
 
#2 ·
i have seen gas go bad in a very short time. the pilot jet is easily clogged in a few months.

yamaha has a water soluble cleaner. you can drain your tank, open drain screws, and pour the mixture of yamaha cleaner and very hot water in the tank.

when it starts coming out the carb drains, close the drains and let set a couple days. if clogging is not too bad, after draining cleaner and filling with fresh gas, should be good to go.

in the 80"s, yamaha developed this because the dealers would have many bikes that sat unsold until carbs clogged, then yamaha had to pay waaranty on each one to remove and clean carbs.

after cleaning, use STA-BIL to keep fuel from fouling for up to a year.

hope this helps.
 
#3 ·
First, just try draining the old gas, put some new gas in, and see if it'll start. If it doesn't then the carb will probably have to come apart and be cleaned. Next time use a fuel stabilizer.
 
#7 ·
According to someone from the Society of Automotive Engineers gas is fine for over a year. After that, as the gas vaporizes, the syrupy remains (also known as varnish) can begin to gum up filters, injectors, carb lines, etc.

I've had gas sit untreated in vehicles for a couple of years that was still fine.

Dump any fuel remains, change filters, use carb cleaning products available at your local auto store, put new gas iin and see if it doesn't run fine.

Worst case scenario is that you'll have to replace lines.
 
#8 ·
I'm no expert, but there are a variety of different gasoline blends that vary from state to state. Some may go bad before others.

I'm in CT. I have a 97 FLHTCI that I filled up last November at the very end of the season. I added some stabilizer to it. Due to an illness, I was unable to ride until just a few weeks ago. The 97 was running just fine with 6 month old fuel. Yet a buddy of mine had a 2 cylinder lawn mower that sat idle for the same lenght of time that wouldn't run right until he replaced the fuel. Who knows? it's a crapshoot I guess. :dunno:

If I have fuel that gets more than about 3 months old, I just start burning it off in my truck or the wife's car a couple of quarts at a time just to get rid of it.
 
#10 ·
I fully believe that gas goes bad, though I haven't seen it as much as one would think. Just this morning I started my chainsaw (totally different I know, 2-stroke, fuel/oil mix, etc) with 4 year old gas in it. Started right up. I usually forget to add Sta-bil to my bike and mowers but they always fire right up with 6 month old gas. Go figure.

I agree about just trying. If it don't start then drain from the carb and refill with fresh and try again. I did the whole carb teardown, remove all rubber, soak in 1 gal can of carb cleaner, rebuild with new gaskets etc. Lots of parts in there! It worked out but it's kinda involved. The pour through stuff sounds much easier if it works.
 
#13 ·
I could be wrong, but I looked in my geerage and all the 2 stroke oil (sears brand) I have has stabil in it, I am no expert on the subject though.

I know this also has no bearing on the orignal post, so I will say my dyna sits for extended time and I put stabil in it and never have a problem starting it, runs crappy till I put fresh fuel in it, but it runs
 
#14 ·
y2kflhr said:
I could be wrong, but I looked in my geerage and all the 2 stroke oil (sears brand) I have has stabil in it, I am no expert on the subject though.

I know this also has no bearing on the orignal post, so I will say my dyna sits for extended time and I put stabil in it and never have a problem starting it, runs crappy till I put fresh fuel in it, but it runs
ok...will have to look next time at sears
 
#15 ·
In the last couple years, I have not seen much of a problem with regular gas.I let the tiller set for about two years, and put fresh gas in it and let it set for about 30 minutes before I started it and it started and ran fine.


On our race cars that we run Alchohol fuel in we flush them out within a day or two after running to avoid them clogging up.

Some guy brought me one to fix and get running for him. It had been run with alcohol and been setting awhile.

AFter I fixed the ignition problem, I could only get it to run when I poured fuel into the carbs.
SO I took the carbs apart and it looked like jello in there.
Cleaned them out and blew out all the passages and they worked fine again.
 
#16 ·
I have heard that ethanol doesn't last as long. I try not to run it in my toys, so don't know. I run it in my bike when I have to, which is often, but it doesn't stay in there for long.
 
#17 ·
gas longevity

yep, i think beserker is correct, although I am not an expert either.

Ethanol fuel (E-10) which we have here in wonderful Massatwoshits, separates real fast. I know in my boat it can reek havoc in 2 stroke motors. And the ethanol gas aint too pretty on carburetors, fuel filters, and sometimes seals.


ace57
'06 flhrs "mattie"
 
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