Gasohol and the Occasionally Used Triumph.

by Paul Higley

I came across a note in a shop manual for a boat engine that went into some detail on the problems gasohol may add to boats not in everyday use. It seems relative to Triumphs that are not in daily use so perhaps it is something we should be paying a bit more attention to as all our gas is now doped with alcohol. The alcohol was added to replace more deadly “Oxygenators” intended to reduce pollution. Spills of these “Oxygenators” turned out to have damaging affects on our ground water. The alcohol can do the same task in reducing pollutants and is politically correct in efforts to reduce gasoline use.

There are two types of “Gasohol”. Methanol or Ethanol can be added to gasoline in up to 10% for standard engines. The Methanol is a problem for “rubber” parts in the fuel system so Ethanol is the alcohol of choice. Ethanol does not create the rubber part compatibility issues but can still be a problem in other ways. Pre-war cars and a few post-war cars used natural rubber and almost anything attacked that. Most post-war cars used synthetic rubber like neoprene and butylenes rubbers with resistance to degradation by low concentrations of alcohols. Recent modern cars have rubber parts that can survive even the 80% alcohol of the new high alcohol fuels even though only a few special design cars can burn this mix.

From what I understand almost all our present gasoline has some alcohol but not more than 10%. The problem noted by this article has to do with water absorption. All alcohols attract and absorb water. This is how the “dry gas” additives work. However eventually this is also a problem as the moisture in the air inside our older TRs is also “dried” by the alcohol in the gasoline we are now putting in the tank. Since we do not all have sealed gas systems, we continue to have new air enter the tank and the moisture absorbed into gas. When the moisture exceeds about 1% the water and alcohol combination precipitates out and sits in the bottom of the tank. The article I found was mentioning this as a problem for boats that are not used every day or even every week as the gas did not get flushed through with fresh low water content gas to keep the water percentage below 1%. This is probably very true for our cars if we are among the majority not daily driving the TRs regularly. It is more of a problem than it has been in the past due to the addition of alcohol in the gas.

So let's here from you. Any comments on this or cures or the reality of the problem? I am not about to drain the fuel system between use to prevent the problem. The information I have on products like “Stabil” say it is intended to hold the volatile components of gas in the liquid formation and prevent it from evaporating so we end up with gas with so low an octane we cannot burn it. I did not see anything about preventing water absorption.

 
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