Re: Carl's 1952 Packard 300

Posted by Owen_Dyneto On 2009/4/29 15:15:12

Re the choke, remember that the tube in the manifold is sealed at both ends at its outside diameter to keep the exhaust gases within the manifold, yet is open at both ends at the inside diameter. The choke line from your Carter automatic choke should enter that tube at the top. The choke uses a small amount of vacuum to draw the air from inside the tube, when the air is sufficiently warm it indicates to the choke that the engine is warming, and the heat from it begins to unwind a bimetallic spring in the choke, allowing the choke butterfly valve to progesssively open.

Regarding the heat riser, you'll have to look more closely, usually the shaft rides in sleeves. A minute amount of leakage is inevitable but normally can't be heard. If yours leaks profusely, perhaps the shaft is severely worn (not too likely), or the sleeves if it has them are worn. Maybe it isn't sleeved and you could bore and sleeve. Others who are particularly familiar with your model will comment in detail.