Rob R. wrote:Finally got a chance to clean things up and take a closer look. Turned out to be a very simple problem. The fitting on the bottom of the fuel tank is slowly leaking, and the fuel was dripping on the valve cover and down the exhaust manifold and engine block. The years of oil and grease being dissolved initially made it look like oil, and there is enough fuel getting inside the exhaust manifold to make it smoke a lot when the engine is started.
I was hoping that cycling the fuel shut off between off and on a few times would cure the leak, but no luck...it is leaking right through the threads on the shutoff. New one is $30 and in the mail.
There are two versions of that shut off, the original Zenith/Bendix one that costs a little more, and the $30 import copy. I stopped stocking that one because of poor quality and lots of leakers. Sometimes, though, you can fix an old leaker if you're careful. There's a little aluminum rivet in the body of the part that stops the shutoff screw from coming all the way out. A very sharp chisel and a tiny hammer can sometimes get the rivet out by getting under its head with the chisel and working around it with the little hammer. If you succeed in getting the rivet to move, and get it out, you can unscrew the shutoff and replace the o-ring in there. That will usually fix it for a long time. Just remember to put the little rivet back in. Jerry