Setting carburetor screws to factory reset - 1988 Toyota Corolla 4 Door

not important, what's important is that they are absolutely clean, including the four brass high speed jets located in the bottom center portion of the carburetor.

That model engine's carburetors has fixed jets, BUT if the slow speed jets are adjustable, earlier model carburetors have been installed. If so...................

The four adjustable needle valves control the flow of fuel in relation to the set air flow, adjusted as follows (if needed).

(Dual Carb V/4 With 4 (2 each carb) Slow Speed Adjustable N/Valves)
(J. Reeves)

The adjustment procedure of the carburetor slow speed needle valves follows. NOTE... if the needle valves turn too freely, replace the nylon bearing retainer (the nylon item at the front of the carb that the needle valve goes through first) with the newer type RED retainer #315232. If your engine has that weird linkage that connects all four of those needle valves, the newer RED retainers will enable you to discard that linkage. The RED retainers make it impossible for the needle valves to vibrate out of adjustment.

(Carburetor Adjustment - 2 Slow Speed Adjustable Needle Valves, each carburetor)

Initial setting is: All (4) Slow speed valves = seat gently, then open 1-1/2 turns.

Facing the carburetors, start with the top left needle valve, then the top right valve, then the bottom let valve, then the bottom right valve. It may be necessary to redo these steps to get the adjustments ideally set

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

Do not attempt to gradually adjust all four of the valves at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

Tuning carburetors and setting timing - Allpar

www.allpar.com/fix/carb-tuning.html
Tuning carburetors on Chrysler, Dodge, and Plymouth vehicles. ... Warm the car upby driving it around for a bit, then connect the vacuum gauge to intake ...

Dodge 440 engine problem???? - RV-Coach Online

www.rv-coach.com/current_category.2178/.../forum_thread_full.html?...
Aug 4, 2005 - 100+ posts - ‎100+ authors My son has a 77 dodge powerwagon with 440. went to replace starter, ... I have changed out the carb, fuel pump,filtters, and coil. .... We have put in a new ignition module, spark advance (vacuum), coil, ... I have a dodge 1 ton Cary Van. ... Where can I find tuneup specs for the '80 440 engine, like plug gap, ...

Dodge carburetor fix: Part 1 - YouTube

? 4:24
www.youtube.com/watch?v=RRcxiDKjzdY
Oct 13, 2009 - Uploaded by 4x4maniac89
Mean Green's carburetor was all gummed up so I took it apart. ... Sometimes it just takes some fine tuning ..

There should only be 1 screw located at the base of the carb facing outward.

The method I use requires a tachometer. If you don't have a tachometer then you can use the "by ear" method, though it's not as accurate.

With the engine off, start by turning the screw all the way in, then back it out 1 and 1/2 turns. This usually give you a baseline to start with.

Start the engine and get it up to operating temperature, make sure the choke is fully open, and have the air cleaner and all vacuum lines installed.

Using the tachometer (or ear) turn the screw (usually out) until the RPMs increase. If they don't increase by turning the screw out, then try turning it in.

Eventually the RPMs will stop climbing while turning the screw (as said earlier, usually out).

THEN turn the screw the opposite direction (usually in) until the RPMs JUST start to drop off. That should be real close to the optimum setting.

This setting is ONLY for the base idle air/fuel mixture and is NOT for anything else.

Hope this helps.

most fuel mixture screws are set initially by turning it all the way in and then backing out 21/2 turns. This should allow start and idle and final adjustment can be done to fine tune it. Check that the idle solenoid is working as it will shut off the idle circuit if it is not

There are only two adjustments on a carburetor, the air mixture setting and the butterfly valve position setting. The air mixture screw is on the side close to the mounting flange, and has a spring behind the screw head to keep it in position.
To adjust it, look for the throttle valve screw which is also on the side, it ix the one that attaches close to where the throttle cable attaches to the carb. Turn the set screw down to let the car idle as slowly as possible. Now go to the air mixture screw. Turn it slowly first in one direction until the revs drop, then turn it out to the point where the revs are maximum. You might have to turn the screw back and forth until you find the best position. Now turn the throttle adjustment back to idle speed.

Sounds like carburetor problems. Does the choke plate open enough to keep engine running? Or the fuel level in the carburetor may be too low-adjust floats for that. Check idle speed settings -idle speed screw. Idle mixture setting-the idle mixture needle.
If still no help, buy a carburetor rebuild kit for it-not expensive, will have all new gaskets and the parts that normally wear in the carb. Instruction sheet and a numbered dismantling sequence will be included in the kit. If you have never taken a carb. apart, let someone who has do the rebuild, an awful lot of tiny parts to keep track of, and you cannot let mix-ups occur. One wrong jet in the wrong place, and you will have to do it over. One check ball that wasn't placed, and you have to do it over. Mechanics are glad that carburetor days are over-fuel injection is more reliable, with about a hundred fewer parts to check on.

set the HSN (high speed needle)screw i all the way then back it out 4 turns this is the factory setting
set the LSN (low speed needle)screw in or out so the screw is flush with the surround then screw in 0.10mm below surface this is the factory setting
now the idle screw screw in or out so you have a gap with brackes on set to 0.50 mm if engine dies open the gap more or if ticks over to fast close the gap more
hope this helps

the idle mixture screws are only for mixture adjustment at idle
at speed the idle circuit acts as a emulsifier tube to help with the fuel in the main jet
what you need is adjustable main jets or fixed jets for that altitude
talk with an accredited carby overhaul shop that knows about the carby you have fitted and the appropriate jets to use

this helped me a lot

CARBURETOR FLOATS SETTING TOO LOW OR MIXTURE SCREWS SET TOO LEAN NEED ADJUSTING.