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All right guys I dun goofed

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Giving it a lot of throttle is different than giving it a lot of gas.  Lots of throttle (gas pedal, or idle speed screw) lets air into the motor, but it allows vacuum to engage 'circuits' or different paths of air/fuel mix.  If your plugs are blackened with suit/carbon and they are not straw colored or whitish, you need more oxygen.  My Z24 gets oil on one cylinder plug, but the wet oil burns down to a bit of a dry deposit that I deal with as regular maintenance. 


Don't install new plugs if they are merely carbon fouled.  You can gently clean the electrodes, just expose some fresh metal on opposing  sides of the electrode with a bit of fine grit sandpaper or Scotch Brite.  Make sure that the gap is correct.  It might take you a while to lean-out the mix and you will clean the plug every time you 'read the plug' and it is dirty.


We need some data here.  Where the accelerator linkage is bolted on to is the shaft for the primary barrel on the DGV, on that side, what size (numbers printed) are on the idle jet (the one accessible without disassembly), what is the main jet (the one on the floor of the bowl), what is the air corrector?  What is correspondingly installed on the other barrel of the carb?  How many turns in for the idle speed screws and the idle mix screw?  You may not want to reinstall the cotter pin that holds the choke linkage every time you remove the top of the carb, pull the top of the carb straight up so you don't damage the float.  Careful with gas spilling near a hot exhaust manifold.


I don't know that a cork is necessary in your manifold.  I'm still confused exactly how exhaust is routed into the intake on that motor, someone please chime in here.  


You need six parts.  Two nuts for the EGR studs, two washers, a gasket, and a plate (I'd fabricate the plate and improvise with the gasket, but I'm poor, talented, and inspired) 

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Cork is no good. A single backfire can pop it back out.

Then it must be completely sealed.....

Exhaust Gas Recirculation is the small measured addition of inert (oxygen poor) exhaust with the air and fuel going into the combustion chamber. Basically it just takes up space and lowers the combustion chamber temperatures. It only happens at part throttle and NOT at idle or full throttle or if the engine is cold. Some engines add up to 20% EGR under tightly controlled conditions.


There will be a finger sized pipe from the exhaust manifold to the ERG valve which is mounted on the intake, usually near the carb base so all cylinders get equal amounts. The EGR is just a valve opened by a ported vacuum signal from the carb above idle and not present at full throttle that (again) usually passes through a temperature valve that only opens when the engine is warmed up. Later models had a BPT back pressure transducer which modified the vacuum signal using exhaust back pressure which is a more accurate indication of engine load. Any leak in the exhaust tube or EGR will allow oxygen rich air in, leaning out the fuel air mixture.

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The plugs are actually good, they are brown and dry. The points on the ignition are good too.


I know the idle jet on the throttle side says 50 and the other says 55 but I don't know about the other ones I'll have a look.


It is running rich even though I've got the idle mix screw in all the way. and lately it seems to want to run 4 or 5 turns out.



It is in a bit of a mood today was starting right up yesterday but not trying at all today so I won't be able to troubleshoot much.




on the one attached to the engine the threads closest to the EGR port are rusted away, to I shoved a cork between that and the tube to try and plug both of them up.

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If not running the EGR you can cut the tube off and pinch and crush it flat and curl it up to seal it using vice grips. Cork will shrink and dry out from the heat and fall out. All you need do is seal the pipe so exhaust doesn't get ot. You can also unscrew it, take it to a fastener shop and get a metric pipe plug and seal it permanently.





It is running rich even though I've got the idle mix screw in all the way. and lately it seems to want to run 4 or 5 turns out.





Something else is causing this. It can run at less than one turn and then need 5.


Read this for setting the Weber adjustments... http://www.carburetion.com/Weber/adjust.htm



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How many turns in on the speed screw?

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if the speed screw is the idle mixture screw i try to keep it about 1 turn out. otherwise not sure.


got new spark plugs today. it has gone from being inconsistently broken to consistently broken. which is good.


instead of either not starting at all or running perfectly it will now start every time and idle really shittily for a few seconds then die. at least it made up its mind and i know it needs a stronger spark. ill try and get it one here

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The idle speed screw is not the idle mix screw.  The mix screw is on the corner of the base of the carb.  The speed screw is what the throttle shaft rests on during idle.  It should be between 1 and 1.5 turns in after it touches the throttle.


When your motor is cold, the choke button should be all the way out, then, after starting the motor, the butterfly should open partly, you may have to just slightly push in on the choke button to make that happen.

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ah the speed screw is all the out. still idles too high, problem with my throttle. choke still wont work, can't give it any gas while starting or after it starts.

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All your symptoms can be explained by not having a choke.


Two weeks ago. Engine will run like shit when cold if the choke not working, if at all.


Do all trouble shooting on a warm engine, 20-30 min of running.


Make damn sure that EGR is SEALED TIGHT. Any air leak will make tuning the carb a bitch.


Idle mix screw should be out 1.5 turns approximately. In less than one turn the jet is too big. Out more than 2 turns it's too small.





 Read what you posted about every time you seal up the EGR it runs better....




All right so this morning I went out, took off my egr cover and put it back on, and the car is a lot better. started normally, can idle for like 10 minutes and I took it on a 10 mile drive, still broken but it only had to stop once.


I was recording when I first tried to start it in the morning, and I stood there recording it for like 10 minutes waiting for it to die and eventually it did. That dying its doing in the end is what it will do on the road when it stops working and exlodes and whatnot.



I wasn't able to pour gas down the carb to see if it would fire because it is starting right up today.


It is also difficult to ignore the fact that every time I try to seal that egr hole better it starts working better. Doesn't make any sense since I've run it for a decent amount of time with no over and then for a while with a really shoddy cover and it didn't make a difference. But it is hella sealed right now if not a little rigged and stuffs still broken though. Maybe indicates something..?




The EGR wouldn't fit back on with the weber. In the pic on their website it looked like they were gonna send me a little seal for it but they didn't, so if anyone knows where to get one of those that would be cool.




The video shows it running pretty much normally so everything is working. I can stress enough how important a sealed up EGR is. You cannot have ANY vacuum leak. That tin cover isn't going to cut it.

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Update on the car have been working on my other car for a while so the datsun hadn't got much attention, thought I would take the distributor out and clean the points and all the electrical contacts on the cap. I schlocked it back in and the car fired up on the first crank, just like it would before it broke. I thought myself a bit of an idiot for not doing that before until two minutes later it died and is right back to its old ways. My starter appears to have given out as well now, not surprising when I'm cranking the car for 10 minutes at a time.

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