Anyone know about 4A-F carb adjustment or have shop manual ?

[Sarwat]

Hi guys, my 1988 corolla with a 4A-F appears to be running very rich and as a result my Catalytic convertor is dead. Before I put a new one on, I'd like to know how I can adjust the fuel mixture ?

I can only find two adjustments one is on the front towards the valve cover and looks to be connected to the choke system and the other is on the firewall side which I belive is the idle speed adjustment.

I have a Haynes manual but it doesn't say anything about the fuel mixture adjustment. If anyone with the Toyota shop manual can look it up for me or scan the page I would be very greatful as I have to get this thing smogged soon.

Also, if anyone has a working used Cat for sale pls let me know.

Thx

[Flashmn]

Theres two adjustments in the back, idlespeed and mixture. The mixture is however pretty much the idlespeed mixture. The carb doesnt have much adjustability also another thing. If the acceleration pump diaphragm breaks, you're gonna be feeding the engine all the time with alot of extra gasoline.

[Sarwat]

Thanks Flashmn. I've taken the air intake off a couple of times but have only seen one adjustment (it has a plastic knob that resembles an odometer or clock gear) and I'm assuming this is the idle speed adjustment ? Where might I find the second and what does it look like ?

Also, how can one adjust the mixture without a sniffer or whatever ?

Finally, where exactly is the accelerator pump and how can I make sure the diaphragm spring is intact ?

Sorry, I don't know much about carbs hence the noob questions :p

Thanks again.

[Flashmn]

Also, how can one adjust the mixture without a sniffer or whatever ?

Finally, where exactly is the accelerator pump and how can I make sure the diaphragm spring is intact ?

Well the other knob its a screw next to the idle speed knob.

It would be hard to get an exact mixture without a sniffer, but you can try to find info on how to tune it by listening.

The accelerator pump diaphragm is inside the carb, theres no replacements. sooo I'm getting some new carbs within the next few weeks

[Sarwat]

Cool, how much is a new carb and where are you buying it from ?

I'm getting over 35mpg so I doubt I'm dumping a lot of fuel in it, but just enough to make it run rich...

I'll take a look at the mixture screw you talk about this weekend, hopefully I can get it to run a bit better.

Thx for all the help, looks like not too many guys have 4A-Fs with carbs or know enough about them