I have a 1977 Toyota 20R pickup. It had been setting (recked/undriven) since 2009. I became the new owner this year and have been working on it. It did pass smog (A MIRACLE) in June (this year). I have replaced many parts that was rusty and warned. I love this truck! I have done all the work myself and wish to continue doing so. But I am stuck right now with carburator a issues. I have studied and studied everything pertaining to my truck. I am pretty sure my problem is the fast idle cam. I believe it is getting stuck when I could start and unsticks when truck starts warming up. It is a very high idle until then. The carb. is OEM. Poor baby is in need of a lot of TLC. Other then that my baby runs great. There could be something missing that connects to it. I can't seem to find a good picture diagram to compare it with. Can someone please give me some input to help me figure this out?

 

Here are the starting procedure for a 22R. Probably the same for a 20R. After starting the truck, if you hit the gas pedal once does the idle decrease?

 

You can spray carb cleaner on the linkage. Don't use anything that's sticky or leaves a residue to clean or lube the linkage.

If you don't have a copy of the service manual, you can download one from this link.
https://web.archive.org/web/20110102...ttora.com/FSM/

 

Your truck series (RN2#)went until 1978. In 1979 the new series became RN3#(2wd) and RN4#(4wd).
If you don't have a repair manual, a very good one that was close to factory quality is Bentley. I don't think they have one for 1977, but they do have one that covers 1978-1984. It might be the best you can get.

15 years is a long time to sit. If it was my carb, i'd source an overhaul kit that has all the gaskets, new float, and needle and seat. Then I'd get a can of carb dip and pull the carb horn and clean, then the carb body. Obviously remove anything rubber or electrical first. If you have access to a large ultrasonic cleaner you could do that before the carb dip. I wouldn't try and remove any of the brass jets, etc. Just strip down enough to safely clean.
After cleaning, reassemble, using the instructions with the kit on setting float height, and see what you got.

 

If it passed smog in June the carb probably doesn't need an overhaul. I would get a carb rebuild kit just to have on hand. Check RockAuto for a kit. If anything is going to go bad it's the diaphragm on the AAP.

Ebay has a lot of Chilton's repair books on these trucks.
https://www.ebay.com/itm/13532981767...90.c101224.m-1


Pic of a 20R carb from my Chilton's repair book.