carbking

Some models of both the Rochester 4-G series and the Carter WCFB series have vacuum passages running vertically inside the carburetor to supply vacuum to the automatic choke unit (airhorn mounted choke). Both companies used velumoid gaskets which tended to shrink over time, thus providing less than a perfect seal for the vacuum passage. If the vacuum seal was damaged, rolling through corners could cause fuel slosh into the vacuum passage. As the engine was calling for very little fuel, the additional fuel entering through the vacuum passage could cause a rich stall (or a severe hesitation). The factory "patch" was to machine an oversize hole in the vacuum passage in both the airhorn and the bowl, and then pressing a small brass tube into the bowl section of the passage. The tube would extend into the airhorn when the airhorn was fitted to the bowl; thus maintaining the position of the gasket and sealing the vacuum passage. Jon.

Reid - you have two issues to contend with. As Jeff mentioned, one is the "swelling" of the zinc alloy. The other is corrosion. A carburetor is a natural Galvanic cell (two dissimilar metals in the presence of a liquid); which causes ion flow. If the carburetor were cast iron, it may be heated to burn the oxygen from the corrosion molecules, but heating the zinc alloy will cause it to crack (or worse, explode violently!!!). If you use liquid nitrogen, keep it on the pump plunger, as the extreme cold on the zinc alloy will also cause it to crack. We have had moderate success by first boiling the unit in water, and then placing the unit in a zip-lock bag and freezing. We then submerge the frozen unit in a weak acid (vinegar, your favorite soft-drink, etc.) to attempt to eat some of the corrosion. We then apply a slide hammer and light upward pressure to the plunger. If something rare, we keep with it. With a unit as common as this one; if it doesn't break loose in a few weeks, we start with another unit. Chances are if/when you get the plunger out, you will find that the well is out-of-round, requiring boring and sleeving for good results. If you have to bore it, a boring bar taking only 1 to 2 thousands at a pass. As Jeff stated, this stuff is extremely weak. A drill bit will normally shatter the zinc alloy. Jon.

While vapor lock does occur, it occurs much less often than diagnosed. A couple of other issues which are diagnosed as vapor lock: (1) Pulling a vacuum on the fuel tank. Many older cars have the tank vent in the fuel tank. Replacing the original cap with a non-vented emissions cap can cause this problem. Make sure that the fuel tank is vented. (2) Break down of ignition system with heat. (3) Replacement electric pump placed too far from the tank or too high above the fuel level. If vapor lock is occuring, it would normally occur at idle or very low speed driving; when fuel demand is very low. The fuel is heated in the line until it turns to vapor, which the fuel pump cannot efficiently handle. One solution is to speed up the passage of the fuel through the fuel line. This can be accomplished by adding a restricted return line from just before the carburetor back to dump in the tank. Since the return line is restricted, the carburetor will receive first "choice" of the fuel. Any fuel not needed by the carburetor will be returned to the tank. This method will normally solve a vapor lock issue. Jon.

What is the carburetor tag number? Jon.

Most accelerator pump circuits have an inlet check valve, and a discharge check valve. Did you make sure that both of these were not stuck in their seats? Jon.

Try Kurt Kelsey in Iowa Falls, Iowa. Jon.

Marcia - also trying to be constructive. There are literature dealers who may have an interest, but you may also find the collection easier to move as well as produce more revenue if you break it by make. I would have an interest in the Pontiac material. I am reasonably sure there are other single-marque collectors who frequent this forum. Cataloging (or pictures) will also make the collection much easier to sell. Jon.

The very best inkjet printer is an inexpensive laser, brand of your choice. Jon.

Just saw the thread, before doing anything else, REMOVE THE REGULATOR!!! Reset the carb to the original specs and see what happens. If that doesn't solve the problem, call me during normal business hours. Jon.

Not really rare, as it appears that most (possibly all) over the counter manifold sales in 1960 were the SD manifold. Seems to be as common, possibly more so, than the regular production unit. However, if everything is there and original, your price is exceptionally reasonable. Very surprised you still have the unit. Jon.

Jeff - take a look at the "carburetor identification" link in a previous post in this thread. Only a few of the Marvels have the number stamped on the edge of the flange. Jon.

All of the factory GM tripowers utilizing Rochester carburetors including Pontiac were set up with the center as the primary carb; and the 2 end carbs as "dumpers". The end carbs have only the main metering circuit and the pump circuit; no power circuit, and no idle circuit. The end carbs should pass no air at idle. Most of the early tripowers utilized vacuum linkage. Some of the later tripowers utilized mechanical linkage. Also, Pontiac at least, had "over-the-counter" mechanical linkage for all years except the 1957. The various Pontiac factory chassis manuals have good information on the tripowers for the applicable years. Jon.

Rand - Marvel carburetors are a pain in the you-pick-the-anatomy-part to identify. This page on our website may help you: Carburetor identification Note that the number you mentioned (10-157) is a CASTING number, not an identification number. Marvel identification numbers are 10-501 and above. Jon.

Stromberg used a "double d" head on the main metering jets. If you remove the main metering jets, you will need a special tool. DO NOT ATTEMPT TO REMOVE THEM WITH NEEDLE NOSE PLIERS!!!!!!! Failure to heed this advice will send you to the local machine shop to have oversize access plugs fabricated. Jon.

Carbking is located in the Baja boondocks of central Missouri, not in St. Louis; but because of the blessings??? <img src="http://forums.aaca.org/images/graemlins/mad.gif" alt="" /> of ethanol, carbking is now too busy producing carburetor parts and kits for recalibration of carbs for ethanol use to accept customer carburetors for restoration. <img src="http://forums.aaca.org/images/graemlins/frown.gif" alt="" /> Another member mentioned the "Junkyard Dog" on the VCCA forums. I can highly recommend this individual, who is also a tech advisor for VCCA. <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" /> Should you have difficulty contacting this individual, give me a call during normal office hours, and I can give you his contact information. Jon.

Thanks to readers of these ads, and the everpresent ebay, I have added more than 60 magazines to the library in the last month. However, no one is offering any of the audio/video items. Please continue to help fill in the spaces. Jon.

Try the Antique Auto Parts Cellar in South Weymouth (Boston) MA. Jon.

Try www.oldihc.org Jon.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Footnote: I figure that in 1938 this car ran perfectly well with the AAV-1, so there's no reason I can't make it do so again with a little effort. <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" /> </div></div> Actually, it did AFTER the engine warmed up, but the auto choke never did work properly. Stromberg tried for two years to get Buick to use the integral choke, but since Delco was a GM company, Buick held on the the Delco choke in 1937 and 1938. In 1939 Buick surrendered (to the better choke assembly), and added a different second supplier (Carter) dropping Marvel. Both Carter and Stromberg were asked by Buick to offer service carburetors (with real chokes) for the 1937 and 1938. MANY of the original 1937 and 1938 Buick carbs were replaced in 1939 by owners who wanted to drive the car if the temperature was below 50 degrees. These were sold in the Buick dealerships. Jon.

The new rubber fuel line is quote alcohol-resistant; which means it will last somewhat longer than the older stuff. Put on a good inline filter, and carry at least one (and the tools to change it) with you. Replace ALL of the old rubber fuel lines immediately, and again every couple of years. Jon.

If you are unsuccessful online, try the reference section of your local library. The Motors Manuals have a pretty good section on Carter carburetors. Or, give us a call during normal telephone hours (see bio). Jon.

Joe - the model D is one of the better Scheblers. If your valve does not leak when seated, it is possible that the float is rubbing the inside of the bowl. Also hopefully you still are using a "gravity feed" fuel supply. The mechanical advantage of the float system of this carburetor will not support an electric pump; unless you have found a pump with a regulated output of less than one pound. Since you seem to have the issue when the engine is shut off, have you checked the tank vent to see if it is clogged. A clogged tank vent would cause pressure which the float/fuel valve could not withstand. Jon.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Joe, Unless it has been replaced with a Schebler, I bet your dad's Buick has a Marvel; that is what came on Buicks exclusively through at least '35. The Marvel has a "cap" (bowl lid), the Scebler doesn't. By the way, we can fix that flooding Marvel here at The Old Carb Doctor. We would update the needle-and-seat system to accept a common-design viton-tipped needle, and manufacture a new cork float with a special coating which modern gas won't harm. This is only part of what we include in a complete carb restoration. Call 800-945-2272 for more details. Jeff Dreibus </div></div> Actually, the earlier Buicks came with Scheblers as original equipment. Kingston, Holley, and Stromberg were also used as O.E. on early Buicks. Marvels came along later. Too bad, the Stromberg was a much better unit. Jon.

Ron - I am aware of this, but the last time I checked, these items were not in that collection. I have been building a private Oakland / Pontiac library for research for about 40 years. Hopefully, some AACA member or literature dealer will be able to fill a few blanks. I don't expect to live long enough to complete the entire library, but working at it. Jon.

The acquisition of literature for our library is an ongoing thing. Particularly interested in completing runs of various magazines published either by Pontiac Division of GM or by GM themselves which would have Pontiac information. Pontiac magazines required (there may be other titles of which I am unaware): Pontiac Warrior Pontiac Owners Magazine Pontiac Co-operation Action Track I have completed the run of Pontiac Safari, so do not require any of these. GM magazines required (there may be other titles of which I am unaware): GM Folks Also very interesting in acquiring audio/video Pontiac materials ie filmstrips, Super 8 filmloops, Tech-Trak, and laser discs. I also have hundreds of duplicates of most of the above which I would be willing to trade. Please help. Jon.