79Chinook

Here's hoping someone can help me figure out what is going on with this bloody Aisan carb. The truck will fire, but the idle is very rough. i am guessing that i do not have everything connected correctly.

the Choke pull off, (one vacuum canister that i do not know how to describe, it holds the throttle partially on and has a set screw), and the power valve are all connected to manifold vacuum.

If i understand correctly this is my AAP:

What kind of vacuum should this be connected to, if any at all?

Also i have this on the side of my carb facing the head:

Can anyone tell me what it is or what it does, i haven't been able to find it on any of the vacuum diagrams that are readily accessible.

hemsingd

Too rich or too lean? How is it off idle?

79Chinook

From the smell of it too rich, the idle is really rough adjusting the timing at the distributor helps even it out, but it dosnt solve the rough idle completely.

kawazx636

iTrader: (3)

I would try just capping them. Most of the vacuum hoses on those Aisin carbs are for emissions any. In fact, before I got my Weber (I would recommend getting one), I desmogged my Aisin carb. I had only 2 vacuum lines. One was the manifold advance to the distributor and the other was the carb advance to the distributor. Everything else was removed and capped off. The fact that you have open ports is basically a huge vacuum leak thus causing your idle problems so try just capping off those two ports and anything else you see that is open.

bone collector

http://www.bluebassdesign.com/boonin/carb_faq/

everything u wanted to know about Aisin carbs...

79Chinook

I have read through the bluebassdesigns page several times before posting, it is very helpful. My only problem is the differences between the 22r carb that is very well documented and my 20r carb that has very little information.

hemsingd

How is the float level? I can't see it through little glass window in your photo. If the float is stuck open etc..

Also I'm not sure if yours has a second vacuum accelerator pump, but it might be good to make sure the diaphragm on it(if it has one) isn't ruptured and flowing fuel into the manifold.

If it is genuinely too rich(it's a little hard to tell sometimes) than I wouldn't immediately suspect a vacuum leak, though that is common everywhere in the world of carburetors.

Also, does it start to run well immediately above idle or does it take some more noticeable throttle to "Clear it out"?

79Chinook

The fuel level is generaly in the middle to the top of the sight glass. Those photos were taken just after my fuel pump decided to die. That has since been replaced with a solid state in line pump that puts out 5-7 psi.

Another question, does the power valve vacuum port need manifold pull, or should it be capped?

hemsingd

I think that if the supporting vacuum control system for the vacuum accelerator pump is gone, then disconnect it. You don't have to cap it on the carburetor IF the diaphragm is okay. Just pull the line - see if gas starts pouring out.

How does the engine react above idle?