What are these screws on a Weber 32/36 (also rough idle cold) SOLVED!

[Scottwattz]

excellent. I will give it a try and let you know. Thanks

[Dudeland]

I am having a rough idle when cold problem and i am trying to figure out what the heck these screws are (not shown is the one near the ported vacuum):

 
Here is a little background on what I've noticed and tried so far, any suggestions would be helpful:
When i start the car cold with the choke engaged it will fire up and run great for about 20 seconds, after that it begins to misfire and progressively gets worse, accompanied by a knock/tapping, until it starts to warm up a little. When at full operating temp is runs fairly well, not perfect but well. 
Another weird note.... unplugging the idle cut-off has no effect.
 
History:
I purchased the car after it had sat in a garage for about 10 years. It ran rough when i managed to get it fired up before doing anything... go figure. Here is what I've done to rectify the lumpy idle since:
-valve adjustment .07 using go/no-go
-rebuilt and re-jetted the carb according to the advice on this forum
-I've done plugs, wires, distributor cap and rotor
-replaced the distributor with a rebuilt cardone, added a hot spark ignition
-removed the resistor wire for the blue coil installed by PO
-removed the smog equipment and wiring, plugging the intake and exhaust manifolds
-sprayed carb cleaner in every possible hole and mating surface i could find with no change to idle
-set timing
-Cleaned contacts and replaced ground wires for battery and alternator ( although i did notice recently that my fuel gauge will occasionally jump while warming up... never does it hot ... hmmmmm a clue maybe? )
-washed the windows and greased the muffler bearings
 
Come on wonderful forum!!! Who's got the magic answer?!!?!?!
 
 
 
 

FWIW the circled bit is for cars with an EGR. Not sure how or why it is this way, but I looked into it and that is all I could find out.


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[Guest zaeos]

9 hours ago, Dudeland said:

FWIW the circled bit is for cars with an EGR. Not sure how or why it is this way, but I looked into it and that is all I could find out.


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Thanks Dudeland!
 

Update: Found a bad ground at the regulator! Now my gas gauge doesn't jump! This however did not affect the rough idle.

 

On another note, I did discover 2 new vacuum leaks! one was at the idle cut off solenoid which i discovered when checking to make sure it functions and noticed i had somehow split the oring.... this did improve the idle some but car was already warm.

 

That, and the fact that i had no more electrical grounds to check, got me thinking maybe this is a vacuum leak still, so i started spraying with carb cleaner again and low and behold when i sprayed it on the throttle linkage where it enters the carb the idle dropped! Is there a seal behind this linkage?

 

Now i'm thinking this could be the reason I had to change the primary idle up to a 65 to get some effect from the misture screw.

 

Edited February 10, 2018 by zaeos

['76mintgrün'02]

8 minutes ago, zeaos said:

Is there a seal behind this linkage?

not a seal, really... but there is a plastic bushing.

 

the plastic bushings are available and cheap.

https://www.pegasusautoracing.com/productdetails.asp?RecId=4130&utm_source=google&utm_medium=cpc&utm_campaign=1586-25&gclid=EAIaIQobChMIq6q0nNya2QIVjLrACh0m6wuVEAYYAiABEgL0DfD_BwE

 

a more expensive and possibly/hopefully more durable option is to install sealed bearings.

https://www.pegasusautoracing.com/productdetails.asp?RecID=5949

 

here is a tutorial on idle adjustment

http://www.carburetion.net/topic/14-weber-3236-dgv-idle-adjstment.aspx

 

Nice diagram here and clicking on the part number brings it up with cost.

http://www.carburetion.net/pages/diagram/weber3236DGV.aspx

[Guest zaeos]

12 hours ago, '76mintgrun'02 said:

not a seal, really... but there is a plastic bushing.

 

the plastic bushings are available and cheap.

https://www.pegasusautoracing.com/productdetails.asp?RecId=4130&utm_source=google&utm_medium=cpc&utm_campaign=1586-25&gclid=EAIaIQobChMIq6q0nNya2QIVjLrACh0m6wuVEAYYAiABEgL0DfD_BwE

 

a more expensive and possibly/hopefully more durable option is to install sealed bearings.

https://www.pegasusautoracing.com/productdetails.asp?RecID=5949

 

here is a tutorial on idle adjustment

http://www.carburetion.net/topic/14-weber-3236-dgv-idle-adjstment.aspx

 

Nice diagram here and clicking on the part number brings it up with cost.

http://www.carburetion.net/pages/diagram/weber3236DGV.aspx

Awesome info '76mintgrun'02 !

 

Thank you! Parts are on order... looks like I'll be pulling the carb again!

I'll report back once they arrive and I have a chance to install!

 

Thanks again everyone for all the great info!

[Guest zaeos]

Update!

I installed the new throttle linkage bushings and re-assembled the carb. I put everything back on the car and now the jetting was too rich. I went back to the 60 main idle jet from 65 and the screw is out 1.5 turns for best idle. 

 

The idle overall is improved a slight bit more, smooooth running when warm, however when cold it still does the same thing but to a lesser degree.... choke and fast idle on, starts and runs great for 20 seconds then gets progressively lumpy till I drive it around the block a couple times. 

 

So i think I'm on the right path with fuel being the issue... and here is something i noticed while in the card the last time... When the main butterfly is closed it doesn't quite cover the tiny hole in the barrel all the way and it looks to me like the butterfly has been digging into the cylinder a little over the years, like it wasn't positioned properly by the PO.... and for the life of me i couldn't get it to operate freely and cover the hole completely.... its only a tiny sliver of the hole but...

 

Anyone think this could be the issue? time for a new carb if I'm so obsessive i can't deal with a little lumpiness in the morning?

 

What do you think FAQ?

 

[TobyB]

Quote

starts and runs great for 20 seconds then gets progressively lumpy till I drive it around the block a couple times. 

The choke's over- choking.  As in, making the mixture too rich.

It's been a while, but I THINK the fix is to increase the idle- up a little- that increases 

revs, so you use less choke, and thus, get less choking...  

 

maybe

 

t

 

[ray_]

3 minutes ago, TobyB said:

The choke's over- choking.  As in, making the mixture too rich.

It's been a while, but I THINK the fix is to increase the idle- up a little- that increases 

revs, so you use less choke, and thus, get less choking...  

 

maybe

 

t

 

 

 

Mine does this too.

 

I was thinking about lessening the spring tension on the choke spring. That assembly is rotate-able. But I haven't.

 

Yet.

[Guest zaeos]

5 minutes ago, TobyB said:

The choke's over- choking.  As in, making the mixture too rich.

It's been a while, but I THINK the fix is to increase the idle- up a little- that increases 

revs, so you use less choke, and thus, get less choking...  

 

maybe

 

t

 

Good thought TobyB! I have had some trouble adjusting the choke... well actually adjusting the fast idle... I can't seem to get it to engage fast idle unless i have the choke closed pretty hard and stomp on the peddle a few times.

 

Any advice on how to adjust the fast idle  and the choke( i have looked btw ).... ?

 

Thanks again! Gettin closer to a smooth running engine is soo exciting!

[ray_]

A good read:

 

http://www.mk3supra.org/topic/561-guide-rebuilding-a-weber-3236-dgav-carb/

[Guest zaeos]

1 hour ago, ray_ said:

A good read:

 

http://www.mk3supra.org/topic/561-guide-rebuilding-a-weber-3236-dgav-carb/

Thanks  ray_! This is the guide i used while rebuilding the first time. However it doesn't really explain how the fast idle is adjusted properly. 

 

I think the issue is i cant get the fast idle to engage unless the choke is fully closed hard. I've fiddled with the fast idle adjustment screw to no avail.

 

Thanks again!

[ray_]

You should be able to tap the pedal when cold, and the choke fast idle cam will move to a detent which will be captured by the adjustment screw. But as soon as you touch the pedal after running, that cam will move and your fast idle will vanish. 

 

That adjustment screw needs to be screwed farther in than you think

 

GL,

[Guest zaeos]

16 minutes ago, ray_ said:

You should be able to tap the pedal when cold, and the choke fast idle cam will move to a detent which will be captured by the adjustment screw. But as soon as you touch the pedal after running, that cam will move and your fast idle will vanish. 

 

That adjustment screw needs to be screwed farther in than you think

 

GL,

Thanks for your patience ray_ ! 

I'll mess with it tonight and report back.

[worzella]

Tangential but your comment about fuel gauge jumpy until warmed up is an oddity I am seeing. My wiring is fresh and my dash gauges are clean and rebuilt so I feel good about grounds etc. 

 

But sure enough my gas gauge is jumpy at start but after she warms up... solid. 

[ray_]

Just now, worzella said:

Tangential but your comment about fuel gauge jumpy until warmed up is an oddity I am seeing. My wiring is fresh and my dash gauges are clean and rebuilt so I feel good about grounds etc. 

 

But sure enough my gas gauge is jumpy at start but after she warms up... solid. 

 

 

Check voltage regulator securing bolt; it's a ground.