What to do with bad gas

No, I don’t need a Tums. What I do need is some good advice. I have old fuel in my gas tank. It’s capacity is 129 gallons and it’s maybe 1/2 to 3/4 full. Not sure. Fuel sender isn’t working. This tank is wedged in the back of my engine compartment behind 2 GM 454 engines. It ain’t comin’ out as long as I own it. I am rigging up a system to pump the fuel out of the inspection port through two in line filters and a water separator then back in through the filler pipe. Probably will recirculate 3-4 times. Will this allow me to make the gas useable?

It depends how old the gas is and filtering wont bring the octane back. The other issue is phase separation which is when the alcohol and gasoline separate and clog things up. We take old gas and mix it with the new gas in our vehicles. They have a computer that will compensate as needed. We own a outdoor power equipment dealership and see it all the time.

Pull a sample out of the tank and see what the stuff looks and smells like. If it's only a couple / few years old (especially if stabilized) and it still looks and smells like gas, I'd add some fresh high octane to wake it up a bit, filter it and run it. If it looks and smells more like varnish, it's too far gone and will need to be pumped out and disposed of.

Unclematt said:

It depends how old the gas is and filtering wont bring the octane back. The other issue is phase separation which is when the alcohol and gasoline separate and clog things up. We take old gas and mix it with the new gas in our vehicles. They have a computer that will compensate as needed. We own a outdoor power equipment dealership and see it all the time.

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The gas is at least 3 years old maybe more. So my best option is to mix in new gas with the old?

Farandaway said:

The gas is at least 3 years old maybe more. So my best option is to mix in new gas with the old?

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Find out what the old gas looks and smells like first. That'll give you an idea of how bad it really is and whether you might be able to save it or not.

rslifkin said:

Pull a sample out of the tank and see what the stuff looks and smells like. If it's only a couple / few years old (especially if stabilized) and it still looks and smells like gas, I'd add some fresh high octane to wake it up a bit, filter it and run it. If it looks and smells more like varnish, it's too far gone and will need to be pumped out and disposed of.

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I’ve considered having it pumped out but I can’t seem to find a place that will do that. It’s in the water at the marina. Seems like a tricky operation. What do I look for when I search for companies that do that?

It depends on what type of gas you have. If it has ethanol in it it is probably beyond saving. If it is ethanol free, called rec gas here, it should be fine. We have used 4 year old rec gas without any issues. We just put some stabilizer in each year and it ran fine. But the ethanol gas will phase separate and then it isn’t to be trusted. It can ruin an engine according to some of the mechanics.

You could pump it out yourself with one of those pumps that attaches to an electric drill and a hose down your fill pipe but it might take a while, and I'm not sure what you do with it once its out.

The thought of using an ELECTRIC drill pump to pump gas terrifies me! If you use a drill pump, better to use an air driven drill with a compressor 30 feet away! Just my take. Once you get the fuel out, I would put in my car 5 gallons/fill up, pouring from the top of the tank if using 5 gallon cans, and if using a 55 gallon drum, leave the last 6 inches or so in drum, pour into a home depot or lowes bucket, if anything is separated, don't use the bottom stuff. Otherwise, in it goes! 5 gallons of old fuel in a 20 gallon or so gas tank is not going to harm anything IMHO.

We had a center console that had ethanol gas in it and we were moving and then the winter came so I couldn’t run it out. I had the local repair shop pump it out. Charged me about $4 per gallon to pump it out and dispose of it. Don’t know what they did with it but from then on I never put ethanol gas in the boat, just rec gas.

Farandaway said:

I’ve considered having it pumped out but I can’t seem to find a place that will do that. It’s in the water at the marina. Seems like a tricky operation. What do I look for when I search for companies that do that?

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You might look at a gas pump for a truck so that it is rated for gas. Pump it into 5 gallon cans. Then just have to figure out how to dispose of it. Be very careful about fumes.

A good fuel conditioner will add combustion efficiency and help a filter system like Racor remove the water. If the gas is a single consistency, it can probably be burned with a good conditioner and octane booster. The carburetors may need cleaning first.

It's a lot easier to go on a cruise than pump out 70 gallons of gas without blowing up.
I've burned a lot of old gas and always made it work in the engine without damage. One option of disposal is to add it to a vehicle that is mostly full.

Chevy 454’s burn just about anything. Certainly I would look at a sample to be sure it’s not turned into something strange. If it looks and spells like gas, use it.

Seafoam
Use a few cans, at $10 each, will make crappy gas useable. Each can is good for a gas tankful on a car, figure 20gal/can.
Then never buy gas that has ethanol in it again.

slowgoesit said:

...The thought of using an ELECTRIC drill pump to pump gas terrifies me! ...

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If you are using a hose there will be no ignition problems. As long as the drill is not right over the boat's fill tube or too close to the receiving vessel there wouldn't be any risk.

Just ask Mel !!

I used to pour old outboard gasoline into my car's fuel tank until last year. The fuel was bad - really bad - and caused a significant repair bill on the vehicle engine. Never again.

Many repair shops in the NE burn waste oil to heat their shops. The mechanic/ owner that does my auto / RV work pumped out a trailerable boat and said he planned to mix it in with his waste oil as long as the volume was small. He is rather conservative and not a shade tree mechanic and the shop is still there so it worked OK.

If you can obtain a 5 gal glass jug , put 5G in and let it sit for a couple of days..

The water & crud will drop to the bottom, pull off the clear gas & dump the rest.

I have a 1978 Chev truck. It will burn just about anything in moderation.

I think dilution is your solution.

pete

While my experience is diesel vs gas, I had about 100 gal of 12+ year old diesel that was dark and smelled like linseed oil. In San Francisco Bay at the time, I was unable to find someone to remove and dispose without a hi-level HazMat protocol. Quote started at $4k. I triple dosed with Standyne and diluted the fuel. My 35 year old Perkins NA 75 HP 4.236 didn't skip a beat. I doubt a newer common rail engine would be as accepting.

Tough call. Sort of depends on how bad the gas is. My home is Florida but I also spend time in mountains of Colorado. The hot/moist climate of Florida really accelerates degradation and decomposition. Absent a reasonable alternative, if your 454s are older with carburetors, I'd be tempted to try running the fuel through them with high quality gas additive plus dilute with hi-octane gasoline (if available) to offset. I wouldn't run WOT though, more of a fast cruise.

Good luck.

Peter

With gas, untreated with stabilizers like StaBil or SeaFoam, much over a year old, I'd certainly dump it. Ain't worth trying to save it.



There are MANY spark proof pumping options to easily remove the gas. The hardest part will be getting the hose to the bottom of the tank.


And could argue to clean the tank while you're at it. More fun.

I just went through this. Had to hire a fuel company to pump out 200+ gallons of unleaded that had been in my tanks for 2 years. It was clear as water, did not have any bubbles or fizz, had no vapors whatsoever, and smelled like used motor oil when it came out. They filled up 4 55g drums.

Pump the gas out, change the filters, flush the fuel lines, change the spark plugs. My twin 454's fired right up, but took a while to clear up and run properly. Thankfully we didn't have to pull injectors.

I mix old with new and run it in my truck every year. The fuels sits in my generator and other things for about a year. I pour it into a larger tank and put new gas on top of it and have never had a problem. That said, I wouldn't do that with a boat or airplane.

toocoys said:

I just went through this. Had to hire a fuel company to pump out 200+ gallons of unleaded that had been in my tanks for 2 years. It was clear as water, did not have any bubbles or fizz, had no vapors whatsoever, and smelled like used motor oil when it came out. They filled up 4 55g drums.

Pump the gas out, change the filters, flush the fuel lines, change the spark plugs. My twin 454's fired right up, but took a while to clear up and run properly. Thankfully we didn't have to pull injectors.

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This is what I really wanted to do. How did you find a fuel company to do that and was your boat in the water when they pumped the fuel out? I really need to hear more.

Constellation1 said:

I mix old with new and run it in my truck every year. The fuels sits in my generator and other things for about a year. I pour it into a larger tank and put new gas on top of it and have never had a problem. That said, I wouldn't do that with a boat or airplane.

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Aviation fuel does not deteriorate...... but it may or may not work in your gas boat.

Farandaway said:

This is what I really wanted to do. How did you find a fuel company to do that and was your boat in the water when they pumped the fuel out? I really need to hear more.

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I googled "fuel polishing company" in my area and found a diesel fuel maintenance company to dispose of it. Cost me a flat $400 including disposal fees. Yes my boat was in the water. They brought out an electric pump that was on a dolly and parked it on the finger pier. Ran a hose through my window and down into my engine room. Removed the sending unit and put a rigid copper pipe into my tank that was attached to a hose. Turned the pump on and filled 4 barrels. I opened up all my windows and hatches, and ran my blower the entire time - although it wasn't as bad as I was expecting it to be.

I went through this several years ago, except it was water in the gas.Hired a fuel polisher. Cost about $400 but I had no problems after

PatSea said:

I went through this several years ago, except it was water in the gas.Hired a fuel polisher. Cost about $400 but I had no problems after

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I didn’t think you could polish unleaded fuel, but I didn’t know it would end up as stinky water after two years either.

I don’t think you can save ethanol gas once it has separated. I would be afraid to chance my engine with it. It would certainly be cheaper to remove it than rebuild an engine.

Pete Meisinger said:

I have a 1978 Chev truck. It will burn just about anything in moderation.

I think dilution is your solution.

pete

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We have a 350 72 Chev PU and I've been dumping old gas from pre-mix outboards and much else and haven’t had a problem for 20 yrs. Had a Suburban w a carb and did it there too.
In the Navy I had a 53 Chev conv 216 six cyl. Had an OB boat w an 18hp Evinrude that took a 24-1 mix. I put up to two 6 gal cans of 24-1 mix fuel in the Chevy just before payday fairly often. Never a problem. No smoke.