Ethanol + fiberglass fuel tanks

Discussion in 'Jet Drives' started by Challenger1, May 13, 2008.

  1. Challenger1
    Joined: May 2008
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    Location: Oldsmar, Florida

    Challenger1 New Member

    I have a 1973 Challenger jet boat with a Jacuzzi jet pump. Having trouble lately with the 455 Olds running rough. Has anyone heard about 10% ethanol in gas dissolving the fiberglass resin in the fuel tanks and eventually causing fuel tank leaks and destroyed engine valves? Do I need to fabricate aluminum or plastic tanks and replace the old fiberglass tanks? Thanks.
  2. charmc
    Joined: Jan 2007
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    Location: FL, USA

    charmc Senior Member

    There is extensive anecdotal evidence that ethanol will dissolve epoxy and polyester resins, causing contamination of the fuel and engine problems ranging from rough running to valve and/or piston damage.

    Use the forum search mode for "ethanol" and variations to find some threads discussing frp tank damage. Searching through Google or similar will also turn up a number of discussions and links to documentation of the problem. Unfortunately, so long as there are ethanol/gasoline blends, the only cure seems to be tank replacement.
  3. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    There's no way of knowing why your motor is running poorly without further investigation, so saying it's definitely the tank is not possible.

    There's also no way of knowing what type of resin your fuel tank is made from either. Some types of resin will hold up much better than others, so it could be fine, or it could be falling apart. With a boat that old I'd replace it if I had even the slightest concern about it's condition.
  4. Accurate twrs
    Joined: Jan 2010
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    Accurate twrs Junior Member

    Challenger1 .... There have been a lot of gas tanks down here in Fla made of fiberglass only to have the ethenol eat them up and ruin the motors..
    Even with an Alum tank it cost me $750.00 to get my yammy back in shape.
    And i did the motor repairs myself... 2 new batteries, fuel filter,injection pump,
    paper filter, clean injectors, squeez bulb. when that motor turned over it was like heaven again...I got away easy, others where not so lucky...
  5. TollyWally
    Joined: Mar 2005
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    Location: Fox Island

    TollyWally Senior Member

    I've spent hundreds of dollars dealing with these issues with metal tanks. The guys with fiberglass tanks have had to replace them at even more cost.

    Thanks dumb *** government, it's bad enough you redistribute my money to buy political support in the corn belt but you messed up my boat too.

  6. Ike
    Joined: Apr 2006
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    Location: Washington

    Ike Senior Member


    Anyway, yes there have been significant problems with fiberglass tanks due to ethanol. It depends on the resin, the age of the tank, whehter nor not it was barrier coated on the inside, what concentration of ethanol, how long the tank has sat with gas in it and so on. There is a lot more than anecdotal evidence on this. BOATUS has done some very substantial research on it. Read Up

    Since I wrote this more research has been done. Google it and you wiill get lots of hits.

    If your tanks are bad it very likely may be due to a combo of problems. Ethanol is not only bad for tanks but also for old fuel lines, old engine gaskets and components. However an engine rebuild, complete with replacing fuel system components with new stuff should resolve that part. You will probably also have to put in a new tank. Frankly I would use metal or Cross Linked Polyethylene roto molded tanks.
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