Expert: Brad Sears - 2/22/2009

Question
QUESTION: I have a 645 D/C Phaeton. Engine rebuilt prox 3000 miles ago. It's been running great since fuel system cleaned out, filter installed, carb tweaked, etc. Original with vacuum tank, Packard updraft carb, etc. I haven't driven it in a few weeks due to weather, so yesterday I took it out. After a few miles, it began missing and backfiring and engine would quit. Fuel was spewing out breather holes in float tank and running out carb. This happened repeatedly during the prox 10 miles trip. Runs 3-4 minutes, then it begins to miss, and quits. Idled in garage afterward and same thing. I've done nothing to the car since last time when it ran great. Any ideas? I'll try to attach pix for grins.

ANSWER: The needle valve in the carburetor has dirt under it or is sticking allowing the float bowl to over fill. A sinking float will do the same thing.
Brad

---------- FOLLOW-UP ----------

QUESTION: That was my next suspicion, tho I can't figure out why it would suddenly do that. I switched out the fuel yesterday and made sure the vent hole in the gas cap was clear. If float is sticking, any advice on solving that?

Answer
One beautiful car! the carburetor needs to be removed and opened up. If you have only two thumbs (my rating system for those who should and should not handle tools, 5 thumbs is a no no) Carefully dissassemble the unit and do a physical inspection. I would get a replacement needle and seat and replace them.
Brad