Hello,

Sharing the information I learned as I had issues with my 1980 20r truck with the stock Aisin carb not idling. The truck would start and run only if I would constantly give the engine gas, so driving was a nightmare as having to break + gas to not stall out + clutch at stop signs/lights was not fun. The stock carb has many many vacuum lines and it turned out that once I finally went through them all, quite a few were wired incorrectly from the previous owner or not plugged in on one end - causing vacuum leaks. If you have old dry lines, and are experiencing vacuum leak like issues then make sure to check your lines! I will share the diagram that I was able to follow to help me get my truck idling!

20r Aisin Carb Vacuum Line Diagram: