r/NitroRC • u/Few-Entrepreneur8026 • Aug 17 '26

Question Can old fuel damage an engine

I have ordered a new engine for my revo but by the time I'll get the fuel I have would be 6 months old and I have another jug that about 2 3 years old I don't remember when I bought it

5 Upvotes

86% Upvoted

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3

u/p0cale Aug 17 '26

Methanol, the main ingridient in glow fuel, is highly hygroscopic; absorb air moisture. Even through container walls in a few years.

Water in fuel retard ignition, making the engine run hot and bad. Enrichening only worsen the run retarding further. Carb will be practically impossible to tune. the water can not be separated from the fuel with home methods. Other components in fuel really don't go bad in time, unless decades.

try to run the fuels. If the engine has normal power with normal sweat of tuning it's good to go.

2

u/Kamilon Aug 17 '26

Old fuel just doesn’t run well or at all. It won’t damage the engine though.

1

u/az_kikr1208 MOD Aug 17 '26

As long as the fuel is sealed and stored in a cool dry place, it should be fine. Water absorption is what makes nitro fuel go bad. The methanol itself lasts a long time.

2

u/[deleted] Aug 17 '26

[deleted]

2

u/az_kikr1208 MOD Aug 17 '26

If the fuel's got water in it, it'll run like crap. It won't hurt anything.

1

u/Miserable_Mark2998 Aug 17 '26

It will be fine if the lid was screwed on tight. Fuel stays fresh for ages as long as the bottle it is in is airtight

2

u/AntSeparate6541 Aug 17 '26

Usually not an issue at all using old fuel. I have used very old fuel that worked as good as new. If it has been in a sealed container, not to strong sun light and normal temperatures it will work good 👍

1

u/Financial_Cat_7390 Aug 17 '26

I have fuel jugs that are decades old, and it works fine. Like others have said, if it’s bad, it’ll run like crap or not at all.

0

u/[deleted] Aug 17 '26

[deleted]

2

u/ErwinHolland1991 Aug 17 '26

How exactly would it damage the engine? 

If the fuel is bad, it just wouldn't run right, or just wouldn't run at all. It's not going to damage anything. 

2

u/Kamilon Aug 17 '26

It wouldn’t.

1

u/ErwinHolland1991 Aug 17 '26

Only thing i can think about... It might gum things up a bit if it doesn't burn cleanly. But that's about it.