calif94577

So I decided I was going to rebuild my carb since it has 250k miles and runs like crap. When I took the air box/filter out me being me I started playing with the throttle and realized that instead of opening with throttle it closes... Now I am no mechanic but that aint right... Here are pics to describe my issue better.

This one shows how it rests by its self-


This one shows what happens when I pull on the throttle cable. The "hammer" pulls back instead of pushing forward hence leaving the valve closed (circled in red)-


This one shows me pushing the lever forward to open the valve the way the hammer should be doing-


What the heck is wrong??? Thank you very much for your help!!!

slow-mo

That is actually normal.

As the secondary throttle has no venturi, the "Air Valve" (that choke plate looking thing), acts as a variable venturi. The secondary barrel is not a true variable venturi but only acts in such a manner because of the Air Valve. The Air Valve needs to close when the secondary throttle (at the base of the carb) opens in order for vacuum to form in the secondary and therefore fuel to flow from it's jets.

This is what is unique to our 22R engines, the "Air Valve" carburetors, whether it be from the trucks or the 22R Celicas. Toyota also uses a traditional 2-barrel, 2-fixed venturi carbs on other cars of the same years. I'm not sure if the Coronas has the 20R or the 22R as well.

calif94577

Sweet, thanks for the info! I was freaking out trying to figure out how to fix it... lol

So how does air get in? And why does it have the ability to open up if it never does? Should it be fully open in the idle position?

Thanks again!

slow-mo

The Air Valve will open as the natural result of the atmpsheric pressure differential between the low pressure below the Air Valve and high pressure above it. High air pressure will push open the Air Valve.

No, it is not supposed to be fully open. Maybe open a little, but as you have observed, whatever open position it is, it will close when the secondary is opened

calif94577

Ok reason I ask is because as you can see there is virtually no difference between throttle open and not. The valve is 98% closed at all times. How open should it be at rest? (no throttle) and how would I adjust that?

slow-mo

With the engine either off or at idle, the Air Valve will be semi-closed.

If you are rotating the throttle linkage so that the secondary throttle valve opens with the engine off, the Air Valve will not open. It will open only with a running engine.

I hope that answers your question.


hmmm...now for that question I will need to look at the book when I get home from work.