B31 spluttering and flashing back through carb

[john11668]

We dont have those options at our pumps . The troublesome fuel was just bought at a local station shortly before this thread started . BP ultimate.

[iansoady]

Well I've never had a problem with ordinary unleaded whether with or without ethanol - sometimes left for 6 months and then starts first kick. Maybe I'm just lucky.

[Rex]

Seems to depend on the engine. My V-twin and lawn mower are both low comp SV's and they need new fuel before they'll start in the Spring. The OHV bikes on the other hand, do fire up on old juice.

[john11668]

Juice was no more than three months old yet apparently clean  ,   New stuff sorted the bike (and made us look like a pair of Idiots) . 
Old juice was  yellowish .   New stuff  virtually clear .

[R]

I once bought a tankfull of fuel for my regular roadbike (at a small servicestation)
and the the performance going up the next hill was so woefull I stopped and checked
my bike was still all present and intact.
I don't know what was in that fuel, but some of it was less than burnable. ?
The next tankfull restored the zip....

Modern fuels seemed geared more towards fuel injection, and are more diesel-like in constituents,
and the more volatile components may be less in evidence - which will affect carbureted engines ?
Fuels apparently are also made to summer and winter formulas, so out-of-season fuel performance
may be less than ideal perhaps.

[john.k]

There was a chain of cut price fuel outlets here that were notorious for fuel problems and engine damage........run by  gentlemen of middle eastern appearance--as the cops say--anyhoo,eventually fined $8 million by the consumer protection for selling recycled paint thinner as fuel,and still on the Customs & Excise wanted list for non payment of fuel excise. ----the proprietor has decided to return to Iran.....Despite the recycled thinner fuel being common knowlege ,it took the feds several years to act.....and in typical government fashion they just stuck fuel excise on all paint thinners...problem solved.

[john11668]

The problem fuel came from a  local station , one of a chain , run by a local cumbrian family and all of their stations sell BP product.
I believe the original problem stuff was their BP "ultimate " whereas the bike is now running fine on 95 Ron regular fuel .

My last runabout was a BMW K100  but I was told by the guy who sold it to me that he found it did not run well on ultimate fuel, and to ensure I used regular .

[Rex]

There's a seller of "Stay-Up" floats for Indians etc in the US, and he monitors fuel quality on a regular basis simply by soaking his floats in fuel for a month or so and monitoring the varying reactions.
His findings seem to match the post above in that he believes industrial solvents are being "disposed of" via the petrol supply chain. Modern vehicles aren't unduly affected due to engine management systems, but our old clunkers can be.

[john11668]

Interesting

[john.k]

On the other hand,I use unleaded as thinner for spraying red oxide......any alcohol ,and the paint curdles and blocks the gun.....Fraction of the price of paint shop supplied thinner...