Just put new carb on 74 slant six and it is different than the old carb. New carb has this bowl vent tube (pic-old one did not). Also has circle shaped hole with little screw hole not found on new carb. What do I do with these? How would the hole get plugged?
1bbl slant pics
- Thread starter TF360
- Start date
-
BillGrissom
Well-Known Member
Appears that both old & new are a Holley 1945. I have the manual, but it shows only an early one like your bottom photo and a later one w/ electric choke. It doesn't show the hole w/ adjustment screw. I wonder if there was a special "clean air" one for CA.
The vent tube went to a charcoal canister. Definitely on 1974 CA cars, not sure about other states. You can find rubber end caps, otherwise a short piece of hose w/ bolt in the end is a redneck fix. However, I don't know that just capping it off will work since I think the float bowl should be vented at idle. Earlier carbs had a vent hole with a rubber disk on lever that opened at idle.
The vent tube went to a charcoal canister. Definitely on 1974 CA cars, not sure about other states. You can find rubber end caps, otherwise a short piece of hose w/ bolt in the end is a redneck fix. However, I don't know that just capping it off will work since I think the float bowl should be vented at idle. Earlier carbs had a vent hole with a rubber disk on lever that opened at idle.
The carb you got is correct for a 1975. The big open tube goes to the position i am pointing to on the charcoal canister. As for the other hole - Mine has a hose fitting pressed into the hole, but there is no opening into the carb. I just stuck a vac cap on it...
You can leave the bowl vent tube open if you want. I do on my TQ carbs. Fuel will not spill out during normal or Spirted driving. On the inside of the carb, there is a mechanical lever that has a rubber disc to seal the bowl vent while driving. It will open slight during normal driving when the pedal is depressed down a bit.
The other spot you point to seems to be sealed. If it is sealed, leave it sealed. No sense opening up a can of worms trying to fix what ain't broke! ;)
The other spot you point to seems to be sealed. If it is sealed, leave it sealed. No sense opening up a can of worms trying to fix what ain't broke! ;)
bcschief
Well-Known Member
The 1st one is the bowl vent the 2nd one appears to be for a feedback solenoid in a later application.
Brian
Brian
BillGrissom
Well-Known Member
I also suspect the mysterious "2nd hole" is for a "feedback solenoid". Those were used on cars starting in the 1980's until "fuel injection" started. I think all of Chrysler's were with the "lean burn" system. My 82 Aries had that (termed "spark computer"), but I don't recall the feedback carb was a Holley 1945. Try looking up the PN to see what engines it was used on. Perhaps slants in Aspen/Volare, Dodge trucks or vans. I don't know if you could even use it without the solenoid. I recall a Holley carb book from then that described how they worked. It looks like the solenoid controlled an air bleed.
-
