yotaman90

Does anybody have any pics of the fuel mixture adjustment screw on the carburetor of an '87 22R? My truck is running WAY too rich and gets horrible gas mileage (14-15 mpg, I had always wondered why). And if its not the mixture, what could it be?

Yodaforce

Horrible? That's not too bad for a twenty year old carb. What did you expect?
Anyhow, do you need a pic to locate the screw? If you know where it is at, turn it in until it starts to idle rough, then turn it out until it idles rough, then turn it halfway back and it should be fine.

yotaman90

A pic would be nice, seeing as I don't have much experience with carbs. Also, I didn't expect 14 mpg form a 4 cylinder engine

dcg9381

I'm not terribly familiar with the mixture adjustment screw on the Asian carb.
On the weber, there was a mixture screw that would adjust idle. Under driving conditions, you were somewhat limited to the mixutre produced by the main jets...
Take a photo of your carb. Sure it's stock?

yotaman90

I would upload a pic, but the one that I have is too big. Also, yes I'm sure that its the stock carb

Yodaforce

I believe that the factory carb has a cap over the screw from the factory. It is on the passenger side of the carb. You have to pop off the cap, and down in the hole is a flathead screw. I have my old factory carb somewhere. If I can find it, I'll look at it.

yotaman90

Thanks, but I think I found it . Problem is that I turned it in all the way, and then backed off 2 1/2 turns (as per chiltons manual), and then started the engine and it was at 2300 rpm! Backed it off 3 more turns and idle returned to 1000 rpm. In other words, when I leaned it out, it idled way higher than normal, and then when I richened it, idle went back to normal. What does this mean? Carb rebuild? Also, idle speed adjustment screw had no affect whatsoever

dcg9381

You need to adjust the mixture screw for highest idle RPM, then make it just a hair leaner.

Impact RPM by adjusting the air into the motor - probably the adjuster that impacts the butterfly, not the mixture.

4banginRunner

14-15mpg is about right with a carbed 4cyl, carburetors are a very inefficient way of putting fuel into an engine, thus the crappy mileage. My 79 pickup with a 20R/4spd was only getting 15mpg.

dcg9381

I'd check with other 22R owners, I don't think 14-15mpg is right for a "stock" truck with a 5sp. I'm thinking +2-3mpg on top of that... or check www.fueleconomy.gov/

Targetnut

A common problem on those carbs is a leaking Auxillary Accelerator Pump (AAP) diaphram. On the side of the carburetor is a small cover that is held on by 3 screws. It has a nipple with a vacuum hose attached. Pull that vacuum hose off and see if fuel leaks out. if so replace the AAP diaphram and check the operation of the TVSV

Also check the choke operation and float level. and check the timing too.

If everything else checks OK then adjust the mixture.

I can't begin to tell you how many times I've had to go behind the owner and re-adjust everything they had mis-adjusted.

4runnerguy

i have a 92 4runner 3.0 v6 and its running rich how do put it running back to normal

dcg9381

You need your own thread - this is a carb issue.

yotaman90

Do you have a pic of the butterfly adjuster, I have no idea where it is, or if it even has one

dcg9381

I don't have a carb'd truck anymore.. There should be an idle adjustment procedure. Have a manual?

yotaman90

I do; but of course, it doesn't say crap