Idle screw question L16/weber

[SHIFT]

The diagram and instructions that came with the weber carb are not clear to me. The instructions refer to an idle screw, idle mixture screw, and a fast idle screw but the diagram does not label anything as the "idle screw". Are there 3 adjustment screws or just 2?

 

The engine is "popping" from out of the carb when I gun it. I pulled one plug and it's black with soot- manual indicates that fuel mixture needs adjustment.

 

My screw drivers are either too long or too short to access some of the screws so I can't count the turns properly... I'm really frustrated.

 

any tips?

[SHIFT]

I just ordered a 90

[datsunaholic]

The mixture screw controls idle mixture only. Power mixture is controlled by the main jets, so the only way to adjust that is to change the jets.

 

There are 3 screws. Fast idle sets the throttle plates when the engine is warming up- based on the choke. When the choke is fully open, the fast idle screw is no longer being used.

 

Regular idle is used to set the idle speed by cracking the throttle open (prevent it from fully closing) and ONLY works when the choke is wide open.

 

Mix is the screw that cranks into the carb base, and only controls how much fuel goes through the idle circuit.

 

 

Popping out the carb has different causes- incorrect timing, or too lean. Black sooty plugs means too rich. This tells me you have 2 problems. You need to get the timing fixed before messing with the carb settings. Of course, it could be too lean at idle and too rich on run, unlikely to cause that much backfiring but possible.

[SHIFT]

The mixture screw controls idle mixture only. Power mixture is controlled by the main jets, so the only way to adjust that is to change the jets.

 

There are 3 screws. Fast idle sets the throttle plates when the engine is warming up- based on the choke. When the choke is fully open, the fast idle screw is no longer being used.

 

Regular idle is used to set the idle speed by cracking the throttle open (prevent it from fully closing) and ONLY works when the choke is wide open.

 

Mix is the screw that cranks into the carb base, and only controls how much fuel goes through the idle circuit.

 

 

Popping out the carb has different causes- incorrect timing, or too lean. Black sooty plugs means too rich. This tells me you have 2 problems. You need to get the timing fixed before messing with the carb settings. Of course, it could be too lean at idle and too rich on run, unlikely to cause that much backfiring but possible.

OK. I have to take this one step at a time... It's time for me to get a timing light. Thank you for letting me know that there are 3 screws.

[SHIFT]

The mixture screw controls idle mixture only. Power mixture is controlled by the main jets, so the only way to adjust that is to change the jets.

 

There are 3 screws. Fast idle sets the throttle plates when the engine is warming up- based on the choke. When the choke is fully open, the fast idle screw is no longer being used.

 

Regular idle is used to set the idle speed by cracking the throttle open (prevent it from fully closing) and ONLY works when the choke is wide open.

 

Mix is the screw that cranks into the carb base, and only controls how much fuel goes through the idle circuit.

 

 

Popping out the carb has different causes- incorrect timing, or too lean. Black sooty plugs means too rich. This tells me you have 2 problems. You need to get the timing fixed before messing with the carb settings. Of course, it could be too lean at idle and too rich on run, unlikely to cause that much backfiring but possible.

The old carb could have been running rich and left the soot as well. If the engine is running lean, what direction do you turn the mix screw?

[denveratsun]

You need to define "running lean"...by that do you mean that at idle, it runs lean? Or do you mean that when throttle is applied it displays a lean condition? A lean "pop" will be evident during partial throttle and beyond...the mixture screw that you are refering to will need to be turned out if a lean condition appears at idle. There will need to be a further discussion on the state of the intake manifold, gaskets, carb, jets, timing, plugs and elevation beyond that.

 

Leaner is meaner...:cool:

 

to a point.:D

 

Check this page for a good insight into your carb....that is of course if you have a 32/36...you did not say what model carb you have.

 

http://www.cjclub.co.il/files/Weber3236adjust.pdf

Edited October 21, 2009 by denveratsun

[ggzilla]

Stock 22RE? Ask in a Toyota forum maybe? I think you'll find that is expected behavior...

[MudThug]

Pirate4x4 forums is the best place to go for that 22re. Sounds normal though. That AC unit is going to create a drag on the motor and possibly kill it at stops. Toyotas fix was probably some sort of idle up solenoid like on an auto to prevent that.

[banzai510(hainz)]

photo

a) is the mixture screw. thurn this in/out till you get a good idle. should be about 1 1/2 turns (turn in all the way till it rest ,then turn out )

 

the fast idle is near the linkage.

 

get correct size screw drivers or buy a Swiss Army Knife!!!!!!!!!!

Edited October 26, 2009 by banzai510(hainz)