pops and bangs when accelerating

Ethanol actually boosts octane so that part of ethanol isn't a problem but it has less energy than gas so there is less power per unit of fuel delivered to the combustion chamber. If the octane rating of regular is sufficient for the engine, there's no benefit to using higher octane.

In my area (MD), all pump gas has ethanol so using premium doesn't get you out of using ethanol. That seems to be different in different parts of the US. You use more gas at the same power setting with ethanol/gas than you would with straight gas and, at max power, depending on the engine's setup and the computer's programming (for cars that have them) you may not be able to make the same HP.

 

I am not sure about anything that floats on water...... I gave up on that money sucking black hole hobby when we left MN and moved to the mountains many years ago.

I read it in a number of different areas related to USCG and SAE when researching the fuel hose problems and trying to find an acceptable, available alternative to making the hose we did. Maybe its a commercial V pleasure craft thing where the USCG has more authority... just guessing at that. I did not believe what I read about the corrosive layer until I was able to duplicate it in my own tests at the shop. Even further, I couldn't believe it would be a problem for us with the cars until I started seeing bands of corrosion around the inside of alloy tanks. I can see where the problem would be multiplied by the extra water a boat is subjected to compared to the limited water a car is subjected to. That point is of little comfort to the BBi owner I had to hammer form and weld in place a whole new tank bottom for.

So much of this is a moving target because there is no way to identify and verify a single cause with the variety of different fuels, additives, storage time.... The best we can do is identify a trend and watch it closely to see if we can find some constants. In the case of a car that was stored for a period of a few months.... I have seen them start up on alcohol and water that separated, run terrible only to have fresh gas eliminate the problem. I too have dealt with carbs full of calcium deposits as well as corrosion in fuel tanks and fuel distributors.

Alcohol by itself is not a problem, many a race car was run on pure alcohol albeit jetted vastly richer than those run on gas. The chemicals used to hold the alcohol in suspension with the gas, then mixed with the water the alcohol absorbs.... That is an ugly concoction that I dont for a second claim to understand the make up of but know full well I dot want it poured on my Whetties.

 

Fouled as in oil or fould as in gas/ carbon? need to source the issue causing the fouling - is this a carb'd car? if not then need to find a Bosch guy to test it up.

 

check ignition dwell(don't know too much about carbed 308, but I assume you have points and such).
replace plugs.
if wires old, replace.
consider replacing wires without extensions (Dave Helms sells up-market wires, or use Taylor spiral-wound); although not needed if using quality connectors, if you do remove the extenders, consider using a centering piece of rubber to relieve stress in the plugs.

with tiny bit of oil, fine; with more oil, conduct compression checks (rings).

 

possible you are running too rich? soot usually means a rich mix, and or carbs are leaking a bit?

My carb experience is limited to a 356 Porsche with Zenith carbs so I'm out of practice... if its just a bit of oil, I guess that is not serious, but oil generally should not be on a plug... so its seeping in some where... valves & guides