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I am trying to adjust the stromberg automatic chokes on my 12, and have found that the vacuum piston on one moves very sluggishly. Do I lub it or just clean it . Thanks Doug
Doug,
There is a vacuum passage in the intake manifold. These often plug up or nearly so. I couldn’t get my chokes to “pull back” when the engine started. I initially blamed the pistons in the choke mechanisms, but no, the real source was the vacuum port. It was completely plugged. You’ll probably need to remove the intake manifolds to completely clean them.
There is also a copper sealing gasket the fits between the choke motor and the intake manifold. You should also check the top of the choke motor for flatness. I had to file mine flat to get a good seal.
Bill
Thanks Bill, I will check the vacuum ports, but I think I cleaned everything pretty well when I rebuilt the engine. The one piston is just too hard to move by vacuum pressure. Should I use some graphit on it or grease? All the service info. just says to see that it works well. Doug
The piston should be dry. Unscrew and remove the brass piece that covers the vacuum port. Then dump the whole thing in a small container of gasoline. The gasoline will dissolve the caked on gook that’s binding it up.
The mechanism should only be restricted by spring pressure. Otherwise it should be free.
Bill
The gas did the trick and everything moves freely now. I blew them off with air pressure and will let them air out. Again thanks for the advice. Doug