1918 Cadillac Carb Info Needed

[Gordon Bartlett]

Gents
      I 'm currently working a on a 1918 57 series w/V8  with carb over flowing issues . My shop pressure gauge  doesn't go down to 1lbs. which manual shows 1.5 to 2.5 lbs. fuel pressure  . The gauge I believe is incorrect , but never been calibrated in my time with car . The Carb overflows out bowl vent tube at base of Carb.  The  needle and seat look wrong to me as The seat is not tapered with very little contact area for seating of needle . I've lapped the needle to remove groove from contact with seat . Either flow pressure high enough to push needle off seat or my needle and seat are not seating as they should .The manual shows a tapered seat in illustration .
Gordon Bartlett 

[EAAR]

Some seats and valves were not tapered but used a ball in the seat.  A seat of that vintage should hold fuel from gravity feed.  Not much pressure.  Is your fuel system pressurized?  I have run electric fuel pumps with regulators set not low levels like 1 lb.  The cork floats get saturated with the new thinner fuels.  They work when they have dried out but then after some time being wet they start sinking.  Neoprene floats do better, but I have seen one of those get saturated.

[Gordon Bartlett]

 Thank You for your reply . I've remade the float from Material I've sourced several times from Restoration Supply and in this case I coated it with Kwik Poly  as the cork one in Carb when it reached me was flaking apart. 
    I find it odd that the Seat is not Tapered ,its almost a square edge that the needle is suppose to seat in . Looking at factory Manual shows a Needle and tapered seat but the picture is a Airbrushed illustration which  could be wrong . Unfortunately I don't trust the gauge for fuel tank pressure since its erratic when blow compressed air in system .The book states 1.1/2 to 2.1/2 Lbs. for fuel pressure and I have not gauge in my tools which reads that low .
I would be interested in seeing what Needle and Seat or Ball and Seat look like ?
  Is there anyone rebuilding the early Carbs.
Yours , Gordon Bartlett

[fishnjim]

I'd be concerned the float is the right density now.   Sinking float could cause overflow.

[Gordon Bartlett]

 Very Good point , I floated it in water but not Gas when I was checking it for Buoyance. Todays gasoline has lower Spec Gravity than old leaded .
It will immediately over flow when starting up after sitting a few days and immediately after disassembling to check over parts . 
     I think I didn't complete my earlier answer in regard to Pressurized system  , It has a Pump on Dash for startup and one working off camshaft on Engine after start up it takes over . In reading over manual it states the engine pump produces less than 1.5 Lbs. when running .
 
Yours  , GordonB