Gasoline/Petrol formulation

It seems within the past year or two, the gasoline suppliers are introducing some different mixes to the pumps.

A couple of years ago I tested some carb o-rings I had bought in bulk by dropping them in gasoline - they didn't swell or change in any way. I still have a supply of those o-rings. I dropped some in some fresh gasoline and the o-rings swelled up to twice their size... ...hmmm.... what is going on?

I don't have any equipment to test fuel, but I'm wondering if alcohol in the mix or other chemicals are causing this.

Anyone in the industry have any insight?

Out here in Kali we have been forced to use gas with 10% ethanol for many years now. It also had MTBE for many years which has now poisoned most of the ground water..... The only thing we know for a fact is that the "oxygenated" gas with the "clean air" additives gives less power and worse fuel mileage.

The diesel truckers have long complained the fuel out here was destroying the seals in their fuel pumps.

Jeff, just curious, were the orings Viton or Nitrile (Buna N)?

13 or 14 years ago I bought an old Dodge that sat for several years. The rubber fuel lines all seemed fine (and I checked) when I bought the car, but after about 2 or 3 fillups, the car just gushed gas out onto the street every where. The fuel lines all turned into a putty or clay-like substance. If you squeezed it, you could mold it like playdough... very disturbing.

I'm not sure what they are. That was the reason I dropped them in gas in the first place. I'd bought them at the local Grainer - and wasn't too sure if they'd hold up to being on a carb drain plug - they did - at least until recently.

They are probably buna-N which does NOT like alcohol of any type. You may want to check into this whole thing but I believe you'll be okay with viton rings. Check with your local Parker-Hanifin distributor or download their online catalogue. It is absolutely full of material compatibility info.

if I remember right viton should be brown
I was wrong they come black or brown

208.72.236.210/html/pg-758252.html

ever since the government mandated that there was to be no more leaded fuels we have been experiancing carb and petcock problems it has gotton really bad in about the last 5-6 years. i have seen myself filling up a bike and less then 5 mins. later watching the petcock o-rings and seals disintagrate before my eyes. carb rebuilds only last half as long as they used to needles and seats are lasting as long as they should. the additive packages that are being added to the fuel to keep the octane levels up are destroying the rubber and brass parts in the carbs escpecally in older bikes this could be the thing that keeps us from riding these bikes as much as we should. some body is going to have to come out with proper replacement kits for these carbs that will stand up to the fuels we have now.i keep hearing about viton as a good replacement but i haven't seen any kits made from this.if you guys have been paying attn. to the post on here 3/4 of them latly have been carb related it is not coincedence.

alcohal carbs?

Viton is a tradename used by Dupont. There is also something called Viton ETP which handles brake fluid in addition to gasoline fuels. Regular Viton is not recommended for brake fluid.

There was some attempt in the industry to color code o-rings, but it never really panned out. As a result many different o-ring materials can look the same, and two o-rings of the same material can look different.