How to clean out an old metal gas tank:

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ksubigbuck

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Here are the results of my experiment, hopefully this will help somebody.

I have 3 old OMC 6 gallon gas tanks. The boat they came out of hadn't been run in 17 years. The old fuel had turned to varnish and the insides of the tanks were coated in varnish and other crud. I had several nice suggestions about how to best clean the tanks and decided to try 3 of them. One note: I removed the float and pickup tube from all three cans so they would not be damaged.

1.On the first tank I poured in about 1/4 gallon of carburetor cleaner and let it sit for two days, sloshing it around once or twice a day. I then took it to the car wash and used a power sprayer to spray all the gunk out. Came out nice and shiny inside! This method works great, but carb cleaner is kinda expensive.

2.On the second tank I used about 1/4 gallon of acetone. I let it sit for two days, then put a dozen large bolts in the tank and shook it for about 5 minutes. Then took it to the carwash and hosed it out with a power sprayer. Worked great. Tank came out nice and shiny and I didn't even blow myself up.

3. On the final tank I didn't use any cleaner. I put about 1/2 inch of water in the tank and dumped in the bolts. Shook 3 different times for about 10 minutes each time. Then went to the carwash and power sprayed it. While it didn't work quite as well as the other two methods, it still worked remarkably well. Only very small traces of the varnish remained. No sediment remained. I am confident that with a couple more sessions of shaking the bolts inside the tank this method would have worked just as well as the first two methods.

Hopefully this helps somebody. Just remember to be careful with flamable liquids and don't blow yourself up. It might be a good idea to use marbles instead of bolts so you don't initiate a spark.

Hunter
 

Rick.

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Re: How to clean out an old metal gas tank:

ksubigbuck: Thanks for the link. It was very interesting to read. Water is a good solution. You mentioned your tanks were full of varnish. Did they also contain any amount of rust, and if so did the rust disappear? Thanks, Rick.
 

redneck88

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Re: How to clean out an old metal gas tank:

not disagreeing with you or anything but wouldnt it be bad to risk running some water through your motor?
 

tashasdaddy

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Re: How to clean out an old metal gas tank:

i think if you drain the tanks well, and set them in the sun with the cap off, the water would evaporate soon enough.
 

tmcalavy

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Re: How to clean out an old metal gas tank:

Good advice on three different methods. You have to loosen the gunk with something first, then put something in to help scrub it a little (nuts/bolts, rocks, gravel...just make sure to get it all out), then use a good power washer. The trick to getting all the water out is to follow with a couple of bottles of rubbing alcohol...the alcohol will evaporate the water as it evaporates. Then let it air dry for a few days, re-inspect the inside and check for holes/rust. Then apply a liquid tank sealer if there's any doubt.
 

ThumbPkr

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Re: How to clean out an old metal gas tank:

I tried to clean out the inside of my bike tank and I chucked a bowden cable in my drill,housing and all and I found that by holding the housing and letting the wire spin inside it I could loosen the sediment fairly well.I just used a garden hose to flush it,a power washer would have been better.
The problem that I had with it is you are fairly limited in the areas that you can reach as the only place I could enter was the gas cap hole.
I think that chemicals to disolve the varnish would be the best wayto do it.I was looking for the cheapest way.:)Ron G
 

xlthompson

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Re: How to clean out an old metal gas tank:

I would NOT use an electric drill because of the sparks form the brushesin the drill mtor. You could go boom!
 

NC State Guy

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Re: How to clean out an old metal gas tank:

glad i found this post. i need to clean out a 30 +/- gallon aluminum tank. it was about 3/4 full of 12 year old gas. i was going to take it to a radiator service, they said their chemical cleaners would ruin the alumininum. so is the acetone or carb cleaner still safe to use? there are also baffles in there, so i don't want to introduce any thing that could get stuck or damage the baffles. Any suggestions? thanks.
 

jimh0911

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Re: How to clean out an old metal gas tank:

thanks for the suggestions on gas tank cleaning, i'm going to try the chain idea, but i dont have a pressure washer, so it may not work, will see.
 

AiricR

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Re: How to clean out an old metal gas tank:

I used a gallon of carb cleaner and 3 cartons of BB's in an old RV tank I had. Just threw it in my truck bed for a week and drove it around.
 

Home Cookin'

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Re: How to clean out an old metal gas tank:

someone suggested taking them to a radiator shop and have them boiled out.
 

jimh0911

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Re: How to clean out an old metal gas tank:

very clever idea thanks, will try it!



I used a gallon of carb cleaner and 3 cartons of BB's in an old RV tank I had. Just threw it in my truck bed for a week and drove it around.
 

sdowney717

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Re: How to clean out an old metal gas tank:

I have used small pea sized rock gravel and vinegar water mixture. Surprisingly, water and vinegar dissolves varnishes.
white vinegar clean metal dissolves rust and cleans oxidation off copper wires for soldering.

alcohol makes a very good carb cleaner. vinegar also works, though the vinegar starts to dissolve pot metals if the metal is left in for several days.
if you clean a carb with vinegar which does work well to get the crud out of small passages, then dont let it sit longer than 8 hours.
I had one carb could not get cleaned out till i used vinegar soak and compressed air..
 

imaboatfan

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Jimh0911 like the original post said.... spend a couple bucks at a car wash if you don't own a pressure washer. Alot of car washes if not most use hot water on the "soap" setting. Then just rinse with home hose afterward. I found gravel works great also.
 

nwcove

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Jimh0911 like the original post said.... spend a couple bucks at a car wash if you don't own a pressure washer. Alot of car washes if not most use hot water on the "soap" setting. Then just rinse with home hose afterward. I found gravel works great also.

.... old thread.
 
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