85 Nissan 720 4x4 Weber.

[Thomas Perkins]

Hi Ya'll.Just like to share something.A couple weeks ago I took my Weber off and put new gaskets on it.Also the little plastic filter and the Accel. Pump Diaphragm Assy..Some of the 32/36 Weber parts have been improved.You can look up the part list and see.Even the  gasket that goes between the 2 parts is a improved one.This is the one that leaks the worse.Some of the old style parts were not working good.One of them is the idle cut off solenoid.I bought one years ago.it was the Redline Weber one and it never would work and I have read a bunch of forums that 720 owners also had problems.I bought a EMPI brand one and put my 0.155 jet in their and it works great.So After I got the Weber put back on the truck and started it,the idle was going up and down.I did remove the idle cut off solenoid when I cleaned the carb. but didn't look at the O ring good.I pulled the idle cut off solenoid wire off of it and it died,so it was working.I then removed the idle cut off solenoid and checked the O ring on it and it was bad.I just bought a bunch from Harbor freight.I put one on it and reinstalled it and it is now working great.The little plastic filter is a new type and slides in there better and doesn't twist when you install the plug.The new gasket is called a air horn and fits better.The Accel.pump Diaphragm Assy. is a new type.These are the 4 improved parts with the 32/36 Weber and I have them except the idle cut off solenoid.The jet that is used on them is the large 0.155 jet.Also if your remove the  fuel inlet pipe that your gas line goes to you will need to replace the fuel inlet gasket to keep it from leaking.I just ordered 6 of them.They are 1.38 each.Here is where I get my Weber replacement parts.When I bought my Weber it would not stay idle with out the idle cut off solenoid..You can't find a Redline 32/36 Weber carb only for 292.00 anywhere.

This large jet is only found on the primary side of certain carburetors, including the ADFA, DGAV ("33B1" variant), and some DGV equipped with an idle control solenoid. It is designed to be held by the idle control solenoid assembly instead of a jet holder. The solenoid extends into the jet to shut off fuel flow when the ignition is turned off.

This jet measures about 0.155" diameter, larger than the more common 32/36 DGV / DGAV Idle Jet (Part No. 1587). Note the consistent OD where the air inlet hole is located in the side of the jet. The larger 4mm push-in flange will not fit in the standard idle jet holder.

The smaller (1/8" diameter) jet, which has a necked down portion around the side air inlet hole, is much more common than this large jet. The small jet is used on the secondary side of all DGV/DGAV/DGEV carburetors, the primary side of most DGV carburetors, and on both sides of many other Weber downdraft carburetors.

Jet sizes refer to the diameter of the fuel outlet hole. Larger size numbers indicate a richer idle mixture. The size of the air bleed hole in the side is fixed (no "F" number variation). Sold individually.

https://www.carburetion.com/diags/3236DGAVDiaginfo.asp Here is the O ring.https://www.pegasusautoracing.com/productdetails.asp?RecID=31711.This site I buy from also...

Edited December 20, 2021 by Thomas Perkins

[DIY 1985]

How many turns in are you on your idle speed screw?  I had the jumpy idle rpm when it was set at like 2 turns in, but, my carb has no idle cut solenoids on the main or secondary idle circuits.

[Thomas Perkins]

I haven't counted the turns.I have it idling around 950 rpm's.By my tac on the dash.It seems if I go lower,it will starve for gas.In the morning,I press the gas pedal to floor to lock in set screw,(cam).It fires right up,I then tap on gas.It goes to down about 1200 rpm's,I wait about a minute,then tap on gas again,then it goes to 950 rpm's.When I get off work,I just turn key with not tapping on gas pedal and it fires up.I have the set screw set at 2000 rpms as Redline says to do.Here is a guide to check your carb.https://www.carburetion.com/Weber/adjust.htm..Also this is a video I did long ago and my Weber is set up the same way but now I have a  Redline Weber.On your's you may need a new O ring on the primary hole.I just put one in mine.It was idling all over the place and adjusting the idle screw did no good cause carb was losing air there.Maybe get a idle cut off solenoid.What do your sparks look like.Mine are burning super clean.Yours probably are getting bad cause of your problem.With your problem,it will cause your's to run rich,it did mine.My idle needle on tac is steady in one place.See where my wires are,red wire to choke,blue wire to idle cut off solenoid.Purrs like a singer sowing machine.Also get a spray bottle with soapy water and spray at base and in middle where other gasket is to see if gasket is leaking when it is running,if it dies down then that could be your problem..I did mine after I installed new gaskets.The O rings need to be changed every so often cause of the heat of the engine.

 

Edited December 22, 2021 by Thomas Perkins

[DIY 1985]

So, I'm at 1.5 turns in on the idle speed screw (throttle blade).

My idle mix screw - unknown number of turns out from seated.

I warm idle at something much lower than yours, but, I never hooked it up to my tach, and I guess it is about 600 rpm, just smooth and low-pitched

 

Primary idle jet is 55

Primary air corrector is 170

Primary main jet is 130

 

Secondary idle jet is 45

Secondary air corrector is 180

Secondary main jet is 135

 

I have a 1 mm hole drilled in the throttle plate - that was the only way I could get the idle speed screw within spec at my Rocky Mountain altitude.

 

My vac is going to affect the numbers above, so this is just my subjective report, and I'd not consider it entirely applicable to a more worn-out Z24, or out of mountain altitude, etc.

 

I have a newer EGR valve and its associated exhaust valve - my old one was rusted internally, so it would have been junk even with just a vac plug to delete the smog set-up.  The best option is a block-off plate between the EGR and intake manifold, if you need to desmog.

 

I'd check manifold vacuum with factory specs at that idle speed, if you can get it there.  Also, check float level drop, if the air horn is off.  Also, make sure valve lash isn't out of spec.  Be sure that the timing light is firing according to the instructions that come with the light (mine is adjustable advance, and it is really easy to accidentally turn the dial on the back of the light), and that it is at Nissan specs for the warm idle rpm.  Check the cap and rotor for oxidation, clean if necessary.