Weber 32/36 DGAV on a L18

[Mydime]

So I am at my wits end with this Weber 32/36 DGAV and am not sure what direction to go. Here is a little info on the setup as of now.

 

Idle Jet: Primary= 55 Secondary= 50

 

Main Jet: Primary= 140 Secondary= 140

 

Air Corrector: Primary= 160 Secondary= 160

 

Pump Jet= 50

 

The problem occurs under load as well as when no load is present. When I hit the accelerator there is a hesitation that occurs for about 1-2 seconds off of idle. Then it catches up to itself and revs fine. If you rev the motor slowly this hesitation is not present. I found that if I manually close the choke flap 1/2 to 3/4 quarters of the way it eliminates the hesitation "stumble" when I rev the motor hard. I have read numerous posts on this issue with no real solution listed.

 

So by closing the choke plates I am limiting the amount of air flowing into the carburetor, therefore creating a richer mixture correct? My question is which jetting should i be looking at richening? I have been told that the Idle jets control up to 2,500 rpm would I want to install a larger idle jet?

 

I have checked the float levels as well as the throttle screw and idle mixture screw they are all set to spec.

 

Any help is more than appreciated!!!!

[datsunfish]

Have you looked to see if the accelerator nozzly is actually squirting gas? A faulty seal on the accelerator diaphragm will cause those problems.

[Mydime]

I have. Carb was rebuilt, new diaphram installed. It squirts a steady stream. Im thinking that Im not getting enough fuel in the idle circuit. Like I described when I close the choke plates partially the hesitation all but dissapears. So less air makes a richer condition. So if I add more fuel ..... in my head...... I imagine that would eliminate the lean condition that I think I am experiencing.

 

It stumbles for just a second or so then catches up to itself. So I think the accelerator pump gives it a shot of fuel, then it stumbles due to lack of fuel, then catches back up to itself when the main jet kicks in.

 

Anyone have any comments or suggestions on my thought process? Suggestions on idle jet size for a L18 should I try going from the 55 to 60.....

[datsunfish]

Actually if you close the choke and it works better its likely a vacuum leak. Which adapter do you have? The 2 piece adapter is notorious for loosening up.

[banzai510(hainz)]

what Datsunfish said about the accell pump. see if gas is being squirted in.

plus loosen the hex nut in back where you put the linkage. soemtimes overtighten it will cause a bind and give a off idle bog.

 

what is your timming set to. Is the dizzy cranked all the way to one side to get it in time? Do you have full movement from )0-20deg BTDC using a timming light? This tells me your pedastal and dizzy will match unless your off a tooth on the oil pump drive.

 

That jetting you have is pretty much standard or slightly on the big side. should be close to perfect for a L20

 

i assume it idles OK. i dont want to find out OH it has a idle cutoff selinoid that wasnt hooked up and you had the speed screw cranked all the way in.

[Mydime]

The adapter plate is a one piece adapter.

 

I do have full movement of the distributor on both adjustment points of the distributor. The timing indicator on the base that bolts to the motor is centered right in the middle of its adjusting range. The 8mm bolt on the bottom of the distributor that is the second adjustmen has movement in both directions as well. Timed at 12 degrees btdc.

 

The electric cut off solenoid is hooked up working properly. It idles great. Idle screw is turned in at 1.5 turns. Idle mixture screw is 2-2.5 turns out.

 

Will get a can of ether and check around the base again to look for leaks. Dont think there are any though.....

 

Any suggestions on jetting for a stock L18. If it is good for an L20 then it might be a little rich for the L18.

 

But as I was saying shouldnt closing the choke flaps limiting the amount of air flow simulate a richer condition? At that point it is when it is running with no hesitation......

[banzai510(hainz)]

yes pulling the choke will usaully create more vaccum to pull more gas to the main circut(meaning main jet)

 

my DGVs that I own I dont even have to turn the speed screw in 1 full turn. But I guess it can vary.

 

I have played with idle jets myself and ran 50 up to 60 and I cant tell the different soemtimes. Some times pulling out a dizzy and swapping with another can give better results if you have that option.

 

 

but if your idleing at 10/12 BTDC I would say you dont have a vaccum leak, But it has to be NO CHOKE. If it only idle with a choke then It could be a vacuum leak.

 

I had also a proplem when I was young(new to datsun) it would cut out right after idle. I though it was the carb only to find out it was the dizzy bushing wore out cause the points to open just be wiggling in the dizzy. a bad capicitor can give the same prolem.

 

I dont know if I helped you or not.

 

Remember dont overtighten that back nut holding the linkage on.

 

is this a used carb?

[Mydime]

It does idle fine with the choke all the way open. When I am off work in an hour im going to pick up a can of ether just to rule out the vacuume leak, I will check the nut on the linkage to make sure that it is not to tight. I will try backing out the throttle speed screw as well and see if that has any affect on it. will keep you guys posted. The carb was used but completely rebuilt. It very well could be the distributor it was from the junkyard and it did just get thrown straight in. Thanks for all the input.

[Mydime]

So hope someone started a betting pool on what the answer would be....Anyone that guessed vaccum leak can put a gold star on the refrigerator LoL. :lol: Ether does not lie. Its cheap and fast use it to check for leaks and save yourself and others time...trying to learn this lesson myself...

 

I pulled the adapter plate that was a one piece forged aluminum.....Found it was warped upon checking it with a sanding block. Took the time cross sanding to both sides were flush.

 

I found that someone had wallowed out the two holes on driver most side of the intake & used jb weld in to hold it all together :blink:

 

Well I the went to fit the adapter plate to a spare L manifold I had and it did not line up....so I assume that is why the previous owner wallowed out the wholes and filled them with jb weld on that other manifold!!!!!

 

In the end I found this awsome cast aluminum high rise adapter for $20, installed it no clearnace issues and no more vaccume leak!!!! No more hesitation!!!! Hope this post can help someone else that may have similar issues.