MoparFins

Techical Discussions => Tech- - FUEL => Topic started by: Bill on May 09, 2008, 01:18:21 PM

Title: Bowls emptying
Post by: Bill on May 09, 2008, 01:18:21 PM
Ok I have a problem with the bowls on the carb drying out.  I know todays gas evaporates quickly but it would seem to me overnight is a bit quick.  I've actually had the monaco in the driveway for the afternoon and had to prime the carb to start her up.  Anyone have any ideas?  It's almost as if the fuel is running out of the carb somewhere but without any venturi action I would assume that's pretty difficult.  Unless maybe she's cracked but everything looked good during the rebuild.
Title: Bowls emptying
Post by: Herman on May 09, 2008, 01:22:29 PM
If your carb gets hot during operation the fuel can evaporate rather quickly through the bowl-vent(s).
You could try a phenolic-spacer under the carb to see if this helps?
Is your heatriser-port blocked off aswell?



Title: Bowls emptying
Post by: Steve on May 09, 2008, 01:31:26 PM
You have a Holley or Carter on that?
Title: Bowls emptying
Post by: Matt Aker on May 09, 2008, 01:36:42 PM
The AFB on my '66 did the same thing.  An older, more learned mechanic told me that the check valve in the top of the carb wasn't seating and was letting the fuel syphon back to the pump.  A rebuild with new components should fix it.
Title: Bowls emptying
Post by: Steve on May 09, 2008, 01:45:38 PM
Or the metering rods are leaking.  That makes more sense 
 
POLARACO2008-05-09 18:46:41
Title: Bowls emptying
Post by: Matt Aker on May 09, 2008, 02:05:47 PM
My problem wasn't as bad after a replacement gas cap.  Once I rebuilt the carb the entire problem ceased to exist.  I know that this diagnosis falls against the laws of physics, but this is what was told to me then, and it werked. (http://moparfins.com/forum/smileys/smiley4.gif)
Title: Bowls emptying
Post by: Steve on May 09, 2008, 02:17:32 PM
I can see the vent stopping the bowl from draining through the metering rods.  But backing up into the needle is impossible.  The needle is not submerged on those.  They're sideways
Title: Bowls emptying
Post by: Matt Aker on May 09, 2008, 02:25:41 PM
My source said that somehow there was a vacuum on the system and the weakest point was the check valve in the underside of the roof of the carberator.  I dunno...  a new gas cap from my partz car and a carb rebuild too care of it.  Maybe David Copperfield or the Lord had something to do with it...  (http://moparfins.com/forum/smileys/smiley5.gif)
 
This was in 1992 and I was an overwieght college student.
Title: Bowls emptying
Post by: Bill on May 09, 2008, 03:06:39 PM
Steve,
 
  It's a carter.  I'd be more inclined to believe the metering rods were leaking.  I hate to buy another rebuild kit just to have the problem persist though.   Any ideas on resolving it besides a new carb?
Title: Bowls emptying
Post by: Herman on May 09, 2008, 03:42:03 PM
Someone please explain how metering rods can leak in a Carter/Edelbrock carb?
They can only 'spill' fuel into the intake when the floatlevel is too high IMO or after shutoff, while the remaining fuel in the bowls heats up and expand, and forces the excess fuel into the intake.



Title: Bowls emptying
Post by: Steve on May 09, 2008, 05:30:06 PM
Metering rods are in the bottom of the bowl on those
Title: Bowls emptying
Post by: Rich on September 28, 2008, 08:38:04 PM
 I had the same problem with eddy carbs -- I gave up and put in an electric fuel pump. I turn it on for 4-5 seconds to let the carb fill up before I start it - no more problems!