Weber DGAV Carb

[D52E]

Posted on the realm:

 

Hi guys, I am having some trouble with the way my car runs (did not run when I bought it). I am having a hard time getting the thing to idle with the Weber DGAV carburetor it has currently. I do have plans to install a pair of DCOE 45 carbs but I want to wait until I finally get the right manifold and rebuild my closed chamber head. For now I just want to try and rebuild/tune the DGAV to get this thing running ok. I ordered a rebuild kit and a gallon of carb dip. After disassembly and cleaning the main body I used compressed air to blow out the passages. I checked the float height and re-assembled the carb and when I went to start the car I had the hardest time to get the darn thing to idle. I had to crank up the idle speed way up for the car to run. The idle is so high that the ported vacuum for the distributor is kicking in and causing even more grief with surging, popping and sputtering at idle. The engine is a L20B that is mostly stock and the carb is using the following jets:

 

 

Main Fuel: Primary 140 Secondary 140

Air Corrector: Primary 170 Secondary 160

Emulsion: Primary F50 Secondary F50

Idle: Primary 50 Secondary 60

 

 

 

I tried spraying carb cleaner on the manifold and carb to look for vacuum leaks but I could not observe any change in the way it ran. For now I have taken the carb back out and re-cleaned it all including the idle jets. I will also plan on changing the manifold and base gaskets just in case.

 

1) Should I use any sealer on these surfaces to make sure there is no leaks (manifold and carb base)? I have seen mixed opinions when it comes to using sealing chemicals on the gaskets and I was wondering how other ratsun members viewed it.

 

2) Also, I noticed that there is a bearing kit for the throttle shafts to fix possible wobble and vacuum leaks (http://www.pegasusautoracing.com/productdetails.asp?RecID=5949). How much movement is normal in these throttle shafts?

 

3) Does anyone have experience using these or maybe just some generic sealed bearings with an inside diameter of 8mm and outside diameter of 12mm (http://www.vxb.com/page/bearings/PROD/Kit7423)?

 

 

Also I do have the right upper gasket installed:

 

[jefe de jefes]

You try this?

http://www.redlineweber.com/html/Tech/carburetor_set_up_and_lean_best_.htm

[ggzilla]

Yeah a lot of those DGAVs are so old and worn out. Get a good carburetor like the Nikki or Hitachi and you'll never look back.

 

I just want to try and rebuild/tune the DGAV to get this thing running ok

So the DGAV did not idle before you added the rebuild kit? Or ran OK, but after rebuild it won't idle?

 

A good carburetor does not need sealant on the gaskets. If this is required to make it run, you have a warped carburetor. My gaskets are 38-years old and not leaking after multiple removals and setting the float ever five years or so.

 

 

How much movement is normal in these throttle shafts?

Normaly is no - none -nada - side to side play. But even if it has a little, it won't prevent the carb from idling. If they are obviously loose it may have trouble idling down.

 

Most common cause of not idling -- but runs fine at 1200 rpm -- is the anti-diesel valve. Does your carb have any electric wires on it?

[D52E]

Jefe:

I did try adjusting it using a similar way (adjust idle speed as low as possible and then tighten mixture screw until idle drops then 1/2 turn out) and repeat. I got the idle as low as possible but it was still very high (no tach but I estimate it was 1500 to 1900 RPM).

 

Its behaving as if it had a big vacuum leak or plugged idle circuit.

 

ggzilla:

I bought the car non-running and when I got it running it was the same as after the carb re-build (no change after re-build).

 

I did take a big file to the base of the carb and filed it to make sure warpage was minimal. I have not changed the gasket between the intake and head yet.

 

The carb does not have a anti-diesel valve (only electrical is choke).

 

Due to the high idle it is hard to detect any major changes when looking for vacuum leaks by spraying carb cleaner on the engine.

[jefe de jefes]

You sure your choke doesn't need to be adjusted?

[HRH]

Use a 45 idle jet instead of the 50. 50 is too big for a stock L20B. Have you adjusted your valves? That and burnt valves can affect tuning of any carburetor quite dramatically. Other than that the 140 mains and a 160/170 air corrector is just fine. Put the 170 in the primary side and the 160 in the secondary side as you need more air in the primary to account for the accelerator pump additional fuel.

 

Sounds like you have either a vacuum leak or crap timing. Or weak ass spark. Check all that stuff. Wiggle your throttle shaft up and down and in and out. If there's play, that's bad.

 

Another thing that will mess you up is if you have the idle set screw to high. It will raise the butterfly past the port in the throat, which fucks everything up. Make sure your throttle plate is damn near full closed, the idle set screw no more than 1 turn to engagement on the stop, run your idle mix adj screw all the way in until stoppage, then bring out 1.5 turns, leave it there, it will be fine. Dick with timing/spark to get it running better at that point. Tweak from there.

[banzai510(hainz)]

your dizzy timmed?

I assume yes.

 

Personally I dont know why Webers needs to be rebuilt so much. I never rebuild them.

 

Is the idle jet clean????? make sure the hole is clean. otherwise yoll have no idle.

 

another thought is if the small thin Weber carb adapte ris used and overtighten it will crack causing the same proplem.

 

A for the idle jet size I dont hink a 45 to 50 is going to make a big deal.

 

make sure the valve lash is good by chance(doesnt hurt to ck)

[metalmonkey47]

Did you check to make sure you have 12 volts to the anti-dieseling solenoid? I had the same problem and didn't have 12 volts, even though I thought I did.

[HRH]

You get it going or what?