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  1. #1
    Seaman
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    Default How do you remove honey-like "tar" from gas tank?

    I have a 1983 17' Boston Whaler, Mntk. This is my first season with her. I have discovered there is a very sticky tar-like substance flowing like honey in the bottem of the tank. Yesterday i drained and removed the tank. put it on one corner and tried to get the sludge to run to one corner. took a rag on a piece of #8 whire and sopped up as much of the goo as I could. got most of it. Once out of the gas it was like a very sticky putty. After it dryed it was hard and shiney. Couldn't find anything to dissolve it! My guess it is there as build up over the years. It started getting into the motor and causing problems. I just installed a fuel filter/water seperator and an inline tempo filter. Figured it is easer to change a filter then redo the carbs. Any idea how I can dissolve the tar to really get the tank cleaned out? thanks

  2. #2
    Supreme Mariner roscoe's Avatar
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    Default Re: How do you remove honey-like "tar" from gas tank?

    What worked for me:Kerosene and a handfull of ball bearings and hex nuts, steel ones so you can get them out with a magnet if need be. Put in tank, shake occasionally, continue till clean, empty out, rinse with a little gasoline.I removed a half inch of dried sludge using this method.Parts cleaner solution should work also.




  3. #3
    Seaman Apprentice
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    Texas
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    Default Re: How do you remove honey-like "tar" from gas tank?

    And to be sure its all clean do this after you complete the above instructions (excellent):Wash it out with scalding hot water, then rinse with vinegar, then water again. Then rinse with alcohol to evaporate the water. Then maybe a chemical tank liner, if the inside looks raunchy and flaky. Then a new in-line fuel filter.Course if you've got a few bucks...its much easier to retire the tank to carry fuel for your mower,chainsaws, etc. and just go buy a new one for the boat.

  4. #4
    Petty Officer 2nd Class
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    Goodland-Hays, KS
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    Default Re: How do you remove honey-like "tar" from gas tank?

    Yea, the lawnmower repair shop will love ya for that!!! If it's a metal "6", trash it and buy a new one...you'll save yourself money in the long run...

  5. #5
    Seaman
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    Default Re: How do you remove honey-like "tar" from gas tank?

    Thanks Guys The tank is about a 20 gal fiberglass/matt tank that came with the boat. I assume it was with the boat when new. I couldn't find anything in my garage to cut the sludge, except acitone. Didn't want to put that into the fiberglass tank, may ruine the tank. Kerosene huh? I just put 20 gals fresh fuel into the tank today and she ran great. Think I may try and get the boat into the garage tomarrow, rain forcast, and take the fuel back out and try the kerosene trick.... Thanks

  6. #6
    Seaman
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    Default Re: How do you remove honey-like "tar" from gas tank?

    P.S. What is the tarlike substance and where does it come from? Once I get rid of this I don't want to have to do this again. Last time I drained the tank Saturday I ran the fuel thru a very fine plastic filter in the funnel. It pluged the funnel once and had to clean it with carb cleaner. When I took the old gaas to the recycle center I poured it out of the tank and the tank's spout had a plastic filter in, with larger holes then the one in the funnel thatI used. After pouring the fuel from the tank there was a clog of tar that was caught by the larger screne!!! The only way it could get to the tank is if passed thru the finer filtering screne in the funnel. This stuff appears to have suspended itself, then later clotted in the tank? If you have any Ideas where it came from pls let me know. Thanks

  7. #7
    Seaman
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    Everett WA
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    Default Re: How do you remove honey-like "tar" from gas tank?

    Probably from the gas going "bad" as it ages. Forms a varnish on the tank, fuel lines, can mess up your carbs or injectors. I always use a fuel addetive (sea foam) to stablize the fuel and help prevent this from happening.

  8. #8
    Captain
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    Default Re: How do you remove honey-like "tar" from gas tank?

    Personally,I would look into a new tank and end your worries which will never end if you clean and use the current tank.Charlie

  9. #9
    Seaman
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    Default Re: How do you remove honey-like "tar" from gas tank?

    Thanks everyone! Roscoe, how long did it take for the kerosene to soften up the "hard tar"? spent the day soaking and shaking the bolts and ended up trying to scrape the tar with a plastic, homade scraper, that didn't work too well. It does work, but not as quickly as I had hoped. She is soaking now and I'll try again in the morning. I can see the crud in the tank and I'll know when she is clean, just cannot get it out. We'll see what the overnight soaking brings. Thanks again to everybody for your help!!

  10. #10
    DJ
    Guest

    Default Re: How do you remove honey-like "tar" from gas tank?

    wuzafed,You can continue to operate on the patient, but I think you're just prolonging the inevitable.Go get a new tank.

  11. #11
    Rear Admiral
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    Default Re: How do you remove honey-like "tar" from gas tank?

    kerosene most likely will be a poorer solvent than gasoline.Try some naptha or paint thinner. But who knows what that will do to the tank. It may looks fine, but later cracks will appear, then comes the leaks, then comes the BOOM!I would buy another one if you can afford it.

  12. #12
    Supreme Mariner roscoe's Avatar
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    Default Re: How do you remove honey-like "tar" from gas tank?

    I did it on a small portable 2.2hp motor that had a built in gas tank. I removed the tank, plugged the outlet, added solution, shook it every couple hours for 2 days, then took it with me when fishing and slowly swirled it around for a few hours. The option of buying a new tank was cost prohibitive, so I just kept at it. I may have added some carb cleaner too, but can't remember.




  13. #13
    DJ
    Guest

    Default Re: How do you remove honey-like "tar" from gas tank?

    Everybody needs to realize that we are dealing with a plastic or fiberglass tank.A lot of chemicals may actually make the situation worse.

  14. #14
    Petty Officer 3rd Class
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    Default Re: How do you remove honey-like "tar" from gas tank?

    Well...let's see.$100-200 for a new tank. or$5000-10,000 for a new outboard motor.I would buy a new tank. Have you priced a new motor lately. Or better yet have you been to a marine mechanic lately?Just my 3 cents worth.Mike

  15. #15
    Supreme Mariner
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    Default Re: How do you remove honey-like "tar" from gas tank?

    hello whoa dont clean or replace that tank. its almost christmas and 1/2 my money comes from old gas and cruddy tanks.the gravy money comes from cleaning carbs and changing filters and such. the big money comes from the motors that run with a partial restriction and smoke a piston. but sometimes it will remove the crankshaft as well as a piston. too bad I dont make money off the parts as well. in all seriousness, I have seen the tank problem you describe on many whalers. they used a red fiberglass tank and it collected stuff on the bottom. we usually replace the tank with another and go on. most solvents that can really cut the goo will cut the tank as well. good luck and be a boater not a customer we will see ya soon enough anyway .
    no tech questions by PM, they wont get answered.
    you have to be trusted by the people that you lie to .

  16. #16
    Seaman
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    Default Re: How do you remove honey-like "tar" from gas tank?

    Thanks everyone for your help! I've put a couple of filters in. One fuel filer/water separator and a smaller tempo in-line filter. Just trying to get another 10 days out of her. (shrimping season closes 11/11). Djohns19 I think your right and I've put in my order with "Santa" for a new tank for Christmas. Just hope I don't regret trying to get a last trip or two out of the old one. Thanks again to everyone

  17. #17
    Petty Officer 3rd Class
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    Default Re: How do you remove honey-like "tar" from gas tank?

    Try some Xylene. Its basically paint thinner. Its already a component of most high octane gasolines (Sunoco 94). Its 117 Octane on its own and can be run up to 30% in a mixture of gasoline to raise its octane. Its commonly used by the Turbo car crowd. Its sensor and catalytic converter safe and won't harm rubber components like alcohol will. I run a gallon in a tank gas in my car to clean fuel injectors once in a while. I am basically trying to tell you its safe to use. I get mine from Sherwin Williams in 5 gallon containers. Never buy those little bottles of injector cleaner, just buy the main ingredient, Xylene.Pour some in your tank, let it sit, I am sure it will disolve it. Don't run the disolved crud through your engine though. Gasoline is not disolving enough of it to harm your engine, Xylene will though. Once clean, add 10% Xylene to the gas mix to clean out the carbs and stuff because if the tank looks like that, the carbs have some in there too.Xyxlene is one part of the really stinky part of commercial caulking. Xylene is the only solvent that will clean some types of caulking.The other option is Toluene, same uses as Xylene, 114 Octane, also found in premium gasolines.You will smell the Xylene in the exhaust if you use it. Then you will be able to smell it in high octane fuel in smaller quantities.

  18. #18
    Rear Admiral
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    Default Re: How do you remove honey-like "tar" from gas tank?

    Xylene will probably make the plastic gas tank brittle.Ken

  19. #19
    Petty Officer 3rd Class
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    Default Re: How do you remove honey-like "tar" from gas tank?

    I wouldn't worry about the tank going brittle. A few hours of Xylene won't compare to the years of gasoline exposure. Besides you have always had traces of Toluene and Xylene in your gas anyway. Bleach will destroy your clothes but you still do your laundry with it.

  20. #20
    Rear Admiral
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    Default Re: How do you remove honey-like "tar" from gas tank?

    Traces of xylene is very different from 100% xylene.When you mix solvents such as gas and xylene, their net sovency is dependant of many things, but it is always less than the "better solvent".I dont know if xylene would make it brittle, but I wouldnt risk it.Ken

  21. #21
    Seaman
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    annapolis, md
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    Default Re: How do you remove honey-like "tar" from gas tank?

    SANTA IS LISNING!

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