carb rebuild

[falente]

Have a 1981 corona with 22R engine and Aisan carb. I want to rebuild carburetor but confused all the different prices and types of kits. As long as I get diaphragms and gaskets what else do I need to be cioncerned with being included in rebuild kit? Found one at autozone for $30.Thanks for any help.

[GeneW1]

Originally Posted by falente

Have a 1981 corona with 22R engine and Aisan carb. I want to rebuild carburetor but confused all the different prices and types of kits. As long as I get diaphragms and gaskets what else do I need to be cioncerned with being included in rebuild kit? Found one at autozone for $30.Thanks for any help.

My experience in rebuilds is strictly limited to US manufacturers. I've done Rochester 2GVs, 4MEs (the electronic four barrel) and I think Carter two barrels (early 1970s vintage).

The typical kit will contain the following....

1. Float or floats
2. check valves/ball valves
3. gaskets
4. cotter pins/snap rings
5. Gages
6. Accelerator Pump(s)
7. Instructions and a parts list.

Most US kits do not contain mixture valve replacements. Often these were covered in a Titanium plug to prevent "tampering". You will be guided in how to remove these if they're in there.

I've never seen diaphragms but vaguely recall them for Motorbike carbs.

What will NOT be in most kits....

Linkages
Vacuum Hoses
Small easily broken parts


The biggest single issue is how you intend to clean the Carb. I have used commercial carb cleaners, which work well. Fresher is best.

Tools...

The kit may contain gages. These will be made of paper or cardboard. You may wish to obtain a set of tools...

You will need....

1. Precision Screw driver set. Also acquire two needle nose pliers, a "hard" diagonal cutter, small punch set and a brass hammer.
2. Metric wrench set, metric socket set and possibly a Torx driver set.
3. Dental Picks (to remove or replace small parts and springs... use something else to clean... scratches will cause definite issues in the future).
4. Adjustment wrenches, not just for assembly/rebuild but to set mixtures. If you do not know what to get ask someone who rebuilds adjusts carbs.
5. Time. You DO NOT RUSH a carb rebuild.
6. A clean area. Carb rebuilds are require cleanliness. It's best if you can have an area where you can work undisturbed and where the carb and parts will not be disturbed. You will need a second area where you can safely use carb cleaner since it smells foul. Drape cloths to cover your work when you're not there would be helpful.
7. Any specialized tools such as angle gages (like a protractor), a caliper and precision ruler. A low level torque wrench would be helpful too.
8. Basins to wash the parts.
9. Compressed air - I've done carb rebuilds without compressed air but the results were crummy. Compressed air will eliminate the garbage inside of small passages and galleys. It's almost an essential tool. You need high pressure and lots of volume, "compressed air" in a can will not cut it.

Some handy tips...

1. Most Carb rebuild kits will give specific guidance on how to rebuild the carb. Most will not give extensive guidance on how to calibrate or set up a carb. Setup of the carb is critical.

Get yourself a Shop Manual. Usually you can go to...

www.helminc.com

However Toyota did not always release Shop Manuals to Helm. You may wish to consult Toyota themselves. I did check for a 1981 Corolla and did not see it there.

However a word of caution - Documentation is important but it is not GOSPEL. Changes due to aging, specific driving conditions, wear and intended use will alter what you need for settings.

Accept that you will have to readjust the carb, perhaps several times. One of my brothers spent months "dialing in" his carb set ups before he was finally satisfied with response.

Be sure that you can call someone if you have questions. I have no experience with 1980s vintage Toyotas. I'm sure that old timers at your local Toyota garage can give you advice.

Setting up the carb is critical. You can potentially damage the emissions control system, transmission (If you have an AT), and even ruin the motor if you are not careful.

A good friend of mine slagged a Mazda by mis setting the Carb. Destroyed the catalytic converter and damaged the motor.



Sometimes it's easier to just buy a bench tested carb "off of the shelf" but even then you have to adjust it to your specific needs.

Good luck. Carb rebuilds are a real test of patience and competence.

Gene

[GeneW1]

A few more things....

Avoid "Tune Up" kits. These are a partial carb rebuild kit that will not completely do the job.

Also be sure that you have the following information....

1. Make of your car and motor. Whether you have an MT or AT.
2. Any ID on the carb, such as serial number or part number. These will be stamped into the carb body or put on a label. If it's a label be certain not to soak it in carb cleaner, you'll dissolve it.



Someone put a lot of time and trouble into setting up your carb at Toyota. They came up with an initial design then they adjusted the final product depending upon how the carb went together on the shop floor and how it performed in testing. Emissions issues also influenced final settings.

Once you open the carb you have to reconsider all of that.....

Free Advice - if you can count the number of turns on any idle mixture screws as you DISASSEMBLE the carb you might be able to "come close" to initial adjustments.

Be cautious while you take the carb apart, noting anything that seems like a mixture setting or adjustable link. Make notes of positions and the number of turns needed to remove a mixture screw or anything that doesn't hold something big together (like the float body, what have you). You can use your notes to get very close to factory settings for reassembly.

Heck, be really thorough and take notes of everything that you take apart. You can't really go wrong doing this.

Gene