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Okay, could someone help me out on this one please?

Posted by rkj 
rkj
I've had gas go bad on me before but 2-3 months? That seems a little soon for gas to turn sour. I know they're putting ethanol in lately but what is making gas go sour; I took the 48 Plymouth's carb apart the other day and it was gummy black around the jets. This carb is only a few years old with probably under a few hundred miles on it. I've also noticed my car (1988 325is/5) having issues lately too; car runs rough as hell after it sits a few weeks or Months if I'm using the 5er. It will even out and get totally better after a few good trips but Jeezz, whats to be done here?

On the bikes I have installed shut-off valves and run them dry if they're going to have to sit for anything longer than a few days and I have a few customers with small collections of cars. I try to run these babies as often as I can but this gas seems to be going off too fast to keep up!

I used stabill in all the cars and seafoam in the bikes (the plymouth had stabill). Is there something better?

Thanks, as always, Rick
Must be the gas blend in your area. I haven't had that problem in SoCal but we have a decidely different blend out here and no ethanol.

Have you checked with other car guys in your area?

alan
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rkj
I took the 48 Plymouth's carb apart the other day and it was gummy black around the jets.... On the bikes I have installed shut-off valves and run them dry if they're going to have to sit...
I think you're on the right track with the shut-off valves.

The float bowl in a carburettor is vented to atmosphere. When left to sit, the gasoline will evaporate from the float bowl leaving behind a gummy mess.

My neighbour used to borrow our snowblower and would simply switch it off when done. It was always hard to start after that. I took the carb apart, cleaned it all up, and it's starts perfectly fine now. Whenever I'm done using it, I turn off the fuel valve and let the engine run until it quits by itself. Never had a problem since.

As for the 325, it's probably just sulking because you drive the 5er too much.
June 21, 2012 11:53PM
I have found that with the ethanol in the gas that it seems to be more susceptible to collecting water. I have had to add some methanol based gas line antifreeze to cure the problem with running rough and faltering.

Bob in Everett
June 22, 2012 05:00AM
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Bob in Everett
I have found that with the ethanol in the gas that it seems to be more susceptible to collecting water. I have had to add some methanol based gas line antifreeze to cure the problem with running rough and faltering.

Could be, Alcohol mixes with water but water does not mixes with gasoline. It's possible that the alcohol and gasoline evaporate and leave moisture and crap concentrated in the tank and lines to clog the carburator or the injection system.
June 22, 2012 07:44PM
The alcohol used in gasoline is ethanol which is hygroscopic, i.e. it takes up water out of the humidity in the air. At least that is what the gas station told me when I complained about getting water from their gas pumps into my car.

Adding the methanol type alcohol seemed to help get the mixture to burn in the engine.

Bob in Everett
June 23, 2012 08:34PM
Hmmm then what's causing the gummy residues?

alan
June 23, 2012 11:20PM
The gummy stuff is what is left after the gasoline evaporates. There are a lot of additives in gasoline to make it perform and lubricate the valves etc. These additives will leave a residue in sufficient quantity.

The rough running of a fuel injected car that has no carburator to collect the gummy residue is that there is some water mixed with the fuel and it causes the combustion to stop intermittently.

Bob in Everett
rkj
June 29, 2012 05:09PM
So, I got some clarity on the gas I put in the Plymouth last December (the owner has his own tank), it was the last of his yearly fill that was sitting all the previous year. He just filled the tank a week ago. I have to think that explains the foul gas in the carburetor, but, I'm thinking a year of sitting in his tank for gas may be a bit long. I think we need to treat the tank with a stabilizer of some kind, 450 gallons.

I still think a shut off is the way to go with these carburettered motors. Running them dry has worked well here with the bikes although you still have to treat what's in the tank. The research I turned up sez the ethanol treated gas around here, as Ferdy says, evaporates and leaves a gummy mess. Which it has on me, and it seems accumulative. Especially if you don't treat the fuel on a regular basis, I use "seafoam" I get at Napa. An once of it per gallon of fuel keeps things clean. These cars and Bikes that sit for periods of time (I'm driving the E30 more these days Ferdy, I promise) really need a dose of seafoam from time to time. Even the one bike I use daily gets an occasional dose, although the bike I use every morning for rehab runs fine on nothing but me!

I have a question for you guys, and girls; what kind/grade of gas do you use in the E30? Some of the research says regular is better because it's fresher. Hi-test sits around too long in the station's tanks.

Thanks, Rick
June 29, 2012 07:57PM
Rick,
Unless you have an M3 or a chip, you do not need anything more than the lowest octane fuel you can buy at the pumps.

I highly doubt that premium fuel sits around for long as there are way too many people who've been brainwashed into thinking premium makes their care go faster and their digits longer winking smiley
rkj
July 01, 2012 11:07PM
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Archeo-peteriX
Rick,
Unless you have an M3 or a chip, you do not need anything more than the lowest octane fuel you can buy at the pumps.

I highly doubt that premium fuel sits around for long as there are way too many people who've been brainwashed into thinking premium makes their care go faster and their digits longer winking smiley

Thanks Peter

I'm glad the E30 runs fine on low-test (the 5er not so good). I think a lot of cars nowadays run on the good stuff with motors running higher compression so you're probably right about the high-test not sitting that long smileys with beer

Best Regards, Rick
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