[Public-List] Progress on fuel issue

isobar at verizon.net isobar at verizon.net
Mon Aug 19 14:12:06 PDT 2013


    Gord... What have we learned so far, by elimination?
   1. Your carb (and engine) are fine since they'll run forever on tank #1
   2. You fuel pump is fine for the same reason. (Vanishingly small chance
   of the marginal higher line length load from tank #2 being disabling)
   3. Your selector valve is fine shown by the double barb test.
   4. The venting of tank #2 is fine shown by the removed gas cap test.
   So, don't waste time worrying about those.
    So what does that leave? Only 2 things I can think of:
   1. Contaminated fuel or gunk in tank #2. A way to test for that would
   be to rig a jumper hose with your double barbed adapter from as close
   as you can get to the tank end of your hose to a can of clean gas. If
   the engine then runs you've got bad gas and you'd have to completely
   re-fuel. There are companies here in Annapolis that do that for you -
   essentially scrubbing out the tank. [Do they exist in the Great White
   North?] I had to have that done with Isobar a couple of years ago when
   I got sand & mud in the tank (Don't ask). That problem led to the carb
   getting gunked up periodically, which doesn't seem to be your problem.
   You might try on you own, siphoning out all the fuel and replacing with
   fresh.
   2. A plumbing failure (my suspicion). You seem to have assured yourself
   that it's not plugged up by being able to blow the hose out cleanly in
   both directions. Then the next logical problem is air: an embolism of
   some sort. Someone mentioned Don Moyer's advice about being absolutely
   sure all connections are tight. You might double check. There might be
   small air leaks in the hose itself somewhere, too. I think Mike Lehman
   gave good advice about maybe having to replace the lines. Also, if the
   fuel line has a hump in it (think air lock) that could stop the fuel
   without being mechanically plugged. Remember how old cars could get
   vapor lock? I'm not sure how to test for a bad line other than rigging
   a temporary bypass hose from the pickup tube in the tank to your
   selector. Maybe it's easier just to follow Mike and replace the damn
   line.
   One more thought: Yoy say that when you switch to #2 the engine dies in
   a "minute or so". That seems to say that you are getting ** NO ** gas
   from tank #2 at all, since it takes a minute or so to use up all the
   gas in carb before being starve of new fuel.

 1376946726.0


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