Packard Forum Index » Pre-War (1899-1942)

Dear All,

OK, I have rebuilt the Detroit Lubricator 51 carb on my 733 sedan (1930). Upon first use, there was a considerable amount of fuel that was freely flowing into the throat and out the air intake. I figured I had not tightened down the float valve seat sufficiently and fuel was running past it.

Took the thing apart, tightened the seat, and it 'seemed' cured. Only problem, it has started again, just slower. No extra fuel when the engine is running, but it definitely is there in the air intake upon letting the car sit overnight. Is there someplace else that I should check, or is it likely that I need to tighten that seat down even further? I really don't like wrenching on the carb, so I may still have been to delicate.

Any help will be much much appreciated.

Best regards,

Tom

I am not familiar with the inner workings of that Carb, but would I say check the float level, as it may be set too high.

But I will let the guys with more experience give the $.02 on the matter.

Also welcome to the Forum! Let us know more about your 733, and if you havent already, please add it to the Owner Registry.

Kev,

Yeah, float level is fine, and the float is fine.

I have already put my two cars in the registry. 1930 733 Sedan and a 1934 1104 Coupe Roadster.

Thanks,


Tom

Cheque the bowl VENT to be sure that it is not obstructed. Cheque the fuel tank GAS CAP to be sure it is VENTED. Is there any fuel spilling OUT of the carb onto the engine?????

Right. The vent for the bowl is present and unobstructed. The gas cap doesn't really have a vent per se, but a gap, and it is open. Also, the 1930 packard 8 was an updraft arrangement, so the excess gas is spilling onto the splash guard behind the generator (starboard side).

How about some strategies for finding the source? The leak is pretty slow, so things like die tracing may not work that well.

Tom

I have posted this question on the AACA Packard forum. BTW, here is a pict of the carb during re-installation.

Tom

Attach file:

---

  (44.32 KB)

Not familiar with inner workings to know if possible but have read of older castings developing "porosity" and "weeping" -especially after being subjected to cleaner and dissolving the varnish coating the bowl.

Tom,

I will weigh in with my two cents. I have had a similar problem with a 1930 Chevy with an updraft carburetor and while it doesn't equate exactly to your problem it might help. The Chevy would gush gas out the air cleaner when the car was running. What I found was the "New" needle with a neoprene tip wasn't doing it's job and cutting off the gas flow at the seat. I changed back to the existing all metal needle and the problem went away. I was later told by a Chevy Guru that they don't like neoprene tipped needles.

You didn't say if you were running the original vacuum system or an electrical fuel pump. If you are running the vacuum system there is a lot of fuel above that needle. Were it my car I think I would pull the lid off the bowl, empty it, dry it out and use a rubber band or similar device to apply gentle upward pressure to the float (simulating the correct level of gas) and see what happens. That should help you to spot your leak. I hope this helps.

Scott

Scott,

Thanks for the info. I will try swapping out the new float needle with the old one (and it's proper seat) and see what happens. It is impossible to remove the bowl cover with the carb installed. I have been pondering some sort of bench rig to do some testing, and I guess I need to do this.

The carb is getting fuel from the vacuum tank via gravity; there is no pump in that part of the circuit.

Again, thanks for the help.

Regards,

Tom

p.s. HH56, I have never heard of that! Again, bench testing will probably tell me. Just have to figure out how to do it!

You're not going to find too many people on this site with familiarity with the Detroit Lubricator updraft carburetor. I suggest you call Daytona Parts (premier carburetor rebuild shop) down in Florida, in my experience they're always willing to spend a few minutes helping old car folks.