Does anyone know what the idle compensator valve does on a 22r carb. When I got my 1986 pickup from my grandpa all the pieces shown in the picture including the valve were missing. When I asked my grandpa about it he said it was causing problems and ran fine without out it (probably thrown away). I recently rebuilt the engine but I am still having major problems with the engine (black smoke still comes out of the exhaust). I know this piece probably doesn't affect the black smoke problem at all but I am trying to get every problem that I know of fixed.... If it wasn't for emissions testing I would just get a Weber carb and be done with it.

 

not sure what it does, but my 87 didn't have that.

 

My my 89 doesn't have one on it . Have you checked the float setting for the flooding problem . The needle valve may also sticking.

 

Yeah it definitely looks like theres a problem with the float and the needle sticking. I'm gonna try and rebuild it tomorrow. As far as the idle compensator valve, I've looked on ebay for 22r Aisin carbs and I found that part is missing on 75% of them. Even if its not going to make a huge difference on how my truck performs, I'm still curious as to what it does.

 

The idle compensator valve was only used on the early model carbs in the seventys and very early eightys, the later model carbs don`t use it even though the space for it is still on the side of the carb.

 

While rebuilding my carburetor I traced the ports going out of the recess for the valve on the side of the carb. One port goes up to the top section of the carb and the other port goes down into the lower portion of the carb. The one going into the lower portion of the carb dead ends inside of the lower portion. So it may be possible to use the valve if the lower port is drilled out (but who wants to do that). In one diagram I found the valve was called a thermostatic valve. So my best guess is that the valve was used in earlier models to let in more gas when the engine was cold and close up when the engine got warm. Just a guess but at least I know now that it isn't contributing to anything bad going on with my engine.

 

it's actually the opposite, it let's air in to cool the carburetor and allow more air through to stop percolating.. mainly for a vehicle with ac when the vehicle stops and idles.