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I bought a 1980 pickup recently that I'm trying to get back up and running. The p.o. had a weber on it that was his friends so he gave me the original aisan 2bbl unattached. I'm having difficulties re-attaching the hoses. Some seem to be missing and some I can't find any info on in the Haynes manual. I'm planning on de-smogging it to make the vacuum lines easier. My question is, what fittings can I plug, what needs to be connected, and where should I route, what i think is the fuel return, right next to the fuel line?
I have a "78 that is similar & has the same carb, & the truck is desmogged. Here's what I have hooked up (descriptions based on your pics for locations):
1. Rear of Carb. 2 large outlets/inlets on back of carb, round piece. This is your choke actuator (some call it a "water choke"), which is coolant controlled, & needs to be hooked up to the coolant system for the choke to work. Corresponding inlets/outlets for it should be just below on intake.
2. Passenger Side, small bent tube on right (towards front of vehicle) next to idle mixture adjustment screw - Vacuum Advance to Distributor. Should go to distributor port furthest away from distributor. There are 2 vac ports on distributor, other port on distributor (closest to distributor cap) is a vacuum retard line & you really don't need to hook that up, just cap it off.
3. Passenger Side, vac port on round item w/3 screws in it, lower right. This is the AAP (Auxiliary Accelerator Pump). This only works if your smog system is functioning properly. It adds a bit more fuel to idle when engine is cold, then shuts off once engine warms up. If not using smog system cap the port. Test for gas leaks from that vac port once you get the engine going again. Leak indicates a ruptured diaphragm, which will give you a bad idle, even with the port capped.
4. Front of carb. Small vac port, 2nd down from top, next to fuel return port. I have this hooked up to the Choke Pull-Off. Choke Pull-Off should be the double diaphragm object @ rear of carb, driver's side next to Choke Actuator. Should be hooked up to outer vac port; cap off inside port. Same advance/retard system as the distributor. you don't need the retard feature.
5. Front of carb. Large Port - Fuel Return Line. This is actually a Vapor Return Line from the Fuel Bowl & goes to your Charcoal Canister.
6. Driver's Side, Large Port on Carb Base - PCV Valve.
Everything else on the carb I have capped off. This is correct to the best of my knowledge; I will of course defer to anyone else out there that has more knowledge on the "80 system.
BTW, it may not help too much as it's not very clear, but here is a link to a vac diagram. It should be the one marked "Fig. 7: Vacuum hose routing-1978-80 20R engines (Federal)"
03-18-2019, 02:34 PM
