Topic: Does old gas turn into white powder?

[bnjnz]

I am trying to prove i've got a good motor before i tear the bike down to rebuild.  I ran gas/seafoam through the carbs and let them soak in place before i try to start the motor.

The #3 carb would drain not any gas the through the drain screw.  When i removed the screw only a large amount of white powder came out of the hole ( table spoon full.) 

I really didn't want to rebuild the carbs just to prove the motor was good, the compression numbers are fair. 

Any thoughts?

[tomkimberly]

If the compression numbers are good, why rebuild the engine?

The carbs are going to need to be rebuilt, might as will do it now. BTW, the white powder is corrosion. You'll see when you take that carb apart.

Tom

[pat english]

its most likely cocaine.

[dave500]

check you have spark and compression,pull the carb rack off,squirt a little gas into each inlet port and try to start it,itll fire and might rev then stop straight away,,if it does its good,sort of,rebuild the carbs another day?or do the carbs and run it with them.

[xsmooth69x]

its most likely cocaine.

make sure to test sniff it and let us know if gas does turn into white powder or if its cocaine

[Bodi]

Gas itself (the petroleum part) just evaporates. If you buy camping fuel naptha - this is pure petroleum distillate very similar to the base stock of gasoline - and evaporate some on a dish you'll see its very clean.
There are additives in pump gas that will remain, usually a  tarry goo.
The bad news is that the additives are slightly corrosive to carburetor metal. Not when mixed in normal gas, but as the evaporation proceeds the remaining stuff is concentrated additives plus there'ssome  dissolved water in the gas. There's also an electrochemical reaction between the brass overflow tube and the alloy bowl that activates in the gas residue soup.
The white powder is your carburetor. Whatever corrosion happened with evaporating gas in there finally dries out and flakes off once all volatile liquid has gone.
With the petcock off, the fuel evaporates fairly slowly (months usually) and the bottom of the float bowl gets corroded a bit. With the petcock on, fuel is added as it evaporates - so after a long while all the tank gas will evaporate in the float bowls. This leaves a deep well of strongly corrosive stuff there dissolving the bowl, float supports, and main jet support. In this situation the carbs are usually way beyond repair.
Even when storing for a winter or more than a month, I suggest you should drain the carbs and disconnect the petcock tube.

[ekpent]

That type of corrosion can be caused by water getting in and reacting with the aluminum. Better pull and clean them well and check them out carefully for damage.That type of corrosion can be serious and cause significant metal loss or pitting.   PS-We have made the Coke joke also when seeing a bowl full of that stuff 

[Duanob]

its most likely cocaine.

Mexican Gas?

I had lots of problems with this occurance. Not sure what causes it but yes, pump gas left to sit and evaporate turns to a white powder substance that clogs small jet ways inside your carbs. Pure pain in the arse.

[bnjnz]

My intent was to see if i could prove up the compression numbers and see if the rings seated better with a warm engine.  At this point i think i am better off just tearing it all down and starting the rebuild. 

It sounds like i need to source at least one carb but i will see what they look like when i get into them.  I have not ruled out swapping in a 400cc motor either. 

But I feel like an idiot, throwing away that much cocaine when theres so many people in the world who don't have any.

[BobbyR]

A lot of the white stuff you find on the emulsion tubes is from the MBTE they banned a while back.

[JoshtheWookiee]

Would Starter Fluid sprayed into the carb cause this?

[dave500]

starter fluid should be going straight into the inlet and be burned,not settling in the fuel bowl,starter fluid like ether dosent leave anything behind anyway although they will contain some sort of lubricant,,bnjnz warming up the engine will improve compression,if its an old been sitting for years engine this may not happen if it has stuck rings that wont expand and other unknown variables like corroded valves etc,,if your doubting the engine and its a long time since it was last run and its unknown otherwise and you want this engine to do more than just run but run well and you want to ride it over distance and have faith in it then do the right thing and rebuild it.