General Category > Quadrajet Carb Talk and Tips

Ram AIR

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Cliff Ruggles:
On my set up the shorter element put the lid too close to the carb.  It ran fine with the taller element and lid further away, and with no lid at all, but hated the lid being close to the carb.....Cliff

motorvation2go:

  I had this very same problem when running a ram air system with the Q-jet.
In my case the filter element was ~ 5" tall allowing plenty of clearance above the air horn/vents etc.
After several attempts to locate the source of a raw gas smell (drive, stop quickly, pop hood, pull breather assy), it was seen that the casting area around the accelerator pump stem was soaking wet with fuel.
Only solution I could come up with was to vent the rear of the breather housing (side closest to firewall) with a few 1.5" holes.
Of course this pretty much defeated any positive pressure feature, however the biggest benefit of cooler air remained.
I vaguely(?) recollect having seen one Q-jet with a thin 'captured' wiper seal installed underside the top carb housing which/where the accelerator pump stem poked through.
Perhaps a  fix?
(If not just a figment of my imagination)... I wonder if these seals are still available?
       

             

71stagegs:
Thanks for reply I wonder if you extented the vent tube past lid?

v737d:
Not an expert by any means but I had this idea,

What if you used a tube vent similar to the type used on a rear axle with the check ball hooked up to the carb vent?


Cheers


Chris

motorvation2go:
Yes this IS an old thread, but I thought it might be helpful to bring it back to the top.
The issue of fuel leakage around the accelerator pump stem (when using a 'ram air' box) is the case in point.
Likely(?) occurs due to higher than ambient pressure in the float bowl combined with normal spray/frothing fuel inlet activity.
Seems later M4ME-M4MC carbs had an accelerator pump single lip(?) upper stem seal w/retainer installed in the underside of the air horn where the stem passes through... emission requirements of the day?
Looks like a potential fix for liquid fuel leakage too.
Did some measuring on my carb # 17080213.
Pump stem Diameter .217"
Counter bore ID of [pump stem] boss underside air horn .346"
C/bore depth .110"
Are the upper stem seal and retainer piece still available?
Thank you in advance.

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