Weber 38/38 DGESHigh idle Adjustment

[DrvnDrvr]

I have a Weber 38/38 on my 83 720 z24 motor that has always performed well but never had a cold start high idle. Found this write on a jeep forum

 

https://www.jeepforum.com/forum/f8/high-idle-kick-down-adjustment-weber-38-dges-2652890/

 

An ole' Southern Gentleman "Mcmud" gave us this info before he passed.

In his Honor, I will pass this along to ya'll.

UPTILLNOW


Electric Choke Adjustment:

The choking devise reduces the air flow into the carburetor and the linkage steps up the idle speed 3-400 RPM. When the engine is cold,this “choking” action will enrichen an already properly tuned engine. This automatic choke consists of an electrically-heated bimetallic coil that will heat and straighten when voltage is applied. Note: This electric choke does not sense engine heat but rather “time” voltage has been applied to it. The average time it takes to straighten the bimetallic strip is 3.5-4.5 minutes. The job of adjusting the choke is to find the time and amount of choking and match that tothe time and temperatures it takes to bring the engine to its full operating temperature.

The amount of choking is determined from your already properly tuned hot engine, but in a cold condition.


#1
The engine and carburetor should be properly “tuned” or adjusted prior to adjusting the choke for a cold engine operation.

#2
The engine must be cold, typically the temperature when starting the engine in the morning after sitting all night.

#3
Loosen (about 1 ½ turns out each) the 3 screws holding the bezel or metal ring supporting the plastic choke element.

#4
With the choke butterfly closed, open the throttle lever and then release. This will activate the high idle linkage. The gap between the idle speed screw and the throttle lever should be approx ¼ inch.

#5
With the throttle lever opened or stepped up ¼” from the choke linkage, rotate the plastic choke housing so the choke butterfly plates open, then rotate the same until the plates almost completely close. This adjustment is made from the engine cold, the choke plates held closed and the throttle linkage opened and on the high idle choke linkage, opening the choke butterfly and closing to a slightly closed position.

#6
Retighten the bezel ring just tight enough so the choke won’t turn. Bottoming out the screws only bends the ring and then comes loose.

#7
Your job is to now determine the timing of the choke operation with the time the engine comes to operating temperature. Adjust the choke rotation closed or open in 1/8 turn increments. Closed (ccw) for a longer duration of choking and open (cw) for lesser duration of choking.

 

and it fixed it. I think it will work on the 34/36 Webers as well. Charlie?

 

 

[datzenmike]

The Weber auto choke is likely one size fits all and has to work on a variety of engines. It's a good starting point setting, but the further north you go will likely need adjusting more towards the rich side or it will come off too soon.

 

I've never seen an engine warm up in 3-5 minutes and my Hitachi never ran well after starting until I adjusted if when sub zero starting. Then it self corrects as the days warm up. If you set the choke tomorrow( late summer) you'll have trouble starting (or poor running) in October when it cools down and have to re adjust it, and again as it gets colder.