1950 Willys Truck re-rebuild by 50wllystrk

3 minute(s) of a 620 minute read

Moving forward on the choke "pull off". The choke pull off is a vacuum diaphram that is hooked up to the choke linkage.

Imagine the choke plate fully closed at cold start, no air going through the carb.

Once the engine starts, it's gonna need some air to continue running or it will flood out, due to too much fuel vs air.

I don't have a vacuum pump or I would have used it to retract the vacuum diaphram arm. For demonstration I pushed the arm to retract it. Then used my finger to block the vacuum hose so I could get a picture of how it works with the linkage.

The vacuum diaphram (choke pull off) you see in the picture, has a vaccum line that goes to intake manifold vacuum. Immediatly as the engine starts, the choke pull off is gonna start to retract the arm comming out of it. It will retract to the point to where it makes contact with the black linkage connected to it in the slot. Once the slotted arm runs out of slot, it will pull on the black liknkage. The black linkage will now work against the spring pressure from the choke thermostat.

The end result is...the choke pull off will open the choke plate around a 1/4" of an inch so the engine can now get enough air to run til the choke thermostat gets warmed up enough to expand the windings. The choke thermostat will now hold the choke plate open from this point on. Til the engine gets cold again and it starts all over again.

Notice the black linkage also has a bend to it. This is also adjustable by either bending it more, or straightening it out. You can set how much air you need to get through the carb while on choke by adjusting the black linkage.

We still have the red linkage hooked to the choke pull off. It is playing a dual purpose. That'll be the next fosus.

On the other hand, the 57 is comming along, slowly, but it's getting there.

I mentioned using a dual electric fan assembly because it moved the fan motors away from the center. This next picture will show what I meant.

The water pump pulley has a pocket into now. Everything has fit just as I wanted. I have just enough room to work on everything.