I need some help please

[Jwalth02]

Put a Weber on it and enjoy life.

Where is the best kit?

[datzenmike]

I would buy a new genuine Weber if I went that route.

[Charlie69]

Pierce Manifolds. They know Datsuns and have been selling Webers and making manifolds for decades.

 

https://www.piercemanifolds.com/

[Jwalth02]

The highest year I see on that site for a 720 is an 82 with the z22 it says.  Should I just call them?

[Charlie69]

Yes call them. I have a 1986 720 king cab that I installed a Pierce Manifolds Weber kit on when I first purchased the truck in 2011.  The carb is still doing fine, passing emissions every 2 years in Phoenix AZ.

Study the Weber and get familiar with them. They are in my opinion one of the simplest carbs made.

 

Keep the throttle linkage plate of of your stock carb and install on the Weber.  Be careful to not over tighten the throttle shaft nut and bend over the nut locking tab to keep nut from loosening.

 

Webers have an inherent problem of having a flat spot if you stomp on the throttle.  This is not a problem if you steadily accelerate.  Some people expect when the secondaries open that you will be thrown back in your seat like a 4 barrel carb opening the secondaries, this is not the case.

 

[Jwalth02]

Well guys, I really appreciate all the help and input you have given me.  I have the idle running a little smoother but still a little choppy.  I have had it on the road once and had no issues, so I think I'm going to run it as is until I decide whether or not to upgrade.

 

Thanks again!

[Charlie69]

Run good gas through it and you might find it runs better.  I run nothing but premium through my trucks.  Keep changing your fuel filters as you did not clean the tank.

[redhead]

Run good gas through it and you might find it runs better.  I run nothing but premium through my trucks.  Keep changing your fuel filters as you did not clean the tank.

 

 

I second this. 

 

I like running non ethanol gas. 

[Charlie69]

I do also but can not get in the Phoenix area.

[redhead]

I do also but can not get in the Phoenix area.

 

That sucks that you can get it in that area.

[captain720]

I love ethanol free, we have 3 stations in town.

[Jwalth02]

Well hello again!

 

I know it's been a while but I wanted to post an update in case it might help in the future.

 

I finally got around to working on the truck again.  Decided to bite the bullet and pulled the carb (wasn't nearly as bad as I thought it would be) I discovered on the smaller barrel (if that's what you call it) there is a oval channel on the side partially covered by the butterfly and when I adjust the idle speed screw you can see more.  LIGHTBULB!  This must be where it gets it's air for the idle?  Well it was full of gunk.

 

I cleaned it out and the four ports next to it as well and the pilot jet directly underneath the butterfly.  Put it all back together and on the truck and OH MY GOD it idles!!!!

 

I adjusted the idle speed screw and the other one that was covered by the plug and got it idling smoothly and at a normal sounding RPM.  Put everything back on thinking I was done and fired it up again to let it idle for a bit and right when I put my last tool away it started sputtering and bellowing white smoke out the exhaust until finally it died.  By the time I got over to it I could hear fuel dripping and the whole side of the carb was covered.  Started it again and fuel was flooding out of the top of the bowl (haven't pinpointed where exactly yet) after the cleaning and before I put it all back together I gave the float a final tweak to get the level right in the center of the dot and it stayed there the whole time it ran until it overfilled and flooded the engine.

 

Now it will continue to do this cycle, open the bowl clean the needle and the seat put all back together, verify fuel level in sight glass, run for 1-2 minutes, overfill bowl, flood and die.

 

Is my fuel pump overpowering the needle you think?  Or maybe I need to pull the seat and clean better?  Why would the level be where it needs to be for a minute then suddenly overfill?  If I adjust the float more it won't be set on the dot.  Maybe tighten it up a little to where it's just below the dot and see if it seals?

 

Thoughts?

 

Thanks again for all your help on this guys.

[Toxicrain]

Well hello again!

 

I know it's been a while but I wanted to post an update in case it might help in the future.

 

I finally got around to working on the truck again.  Decided to bite the bullet and pulled the carb (wasn't nearly as bad as I thought it would be) I discovered on the smaller barrel (if that's what you call it) there is a oval channel on the side partially covered by the butterfly and when I adjust the idle speed screw you can see more.  LIGHTBULB!  This must be where it gets it's air for the idle?  Well it was full of gunk.

 

I cleaned it out and the four ports next to it as well and the pilot jet directly underneath the butterfly.  Put it all back together and on the truck and OH MY GOD it idles!!!!

 

I adjusted the idle speed screw and the other one that was covered by the plug and got it idling smoothly and at a normal sounding RPM.  Put everything back on thinking I was done and fired it up again to let it idle for a bit and right when I put my last tool away it started sputtering and bellowing white smoke out the exhaust until finally it died.  By the time I got over to it I could hear fuel dripping and the whole side of the carb was covered.  Started it again and fuel was flooding out of the top of the bowl (haven't pinpointed where exactly yet) after the cleaning and before I put it all back together I gave the float a final tweak to get the level right in the center of the dot and it stayed there the whole time it ran until it overfilled and flooded the engine.

 

Now it will continue to do this cycle, open the bowl clean the needle and the seat put all back together, verify fuel level in sight glass, run for 1-2 minutes, overfill bowl, flood and die.

 

Is my fuel pump overpowering the needle you think?  Or maybe I need to pull the seat and clean better?  Why would the level be where it needs to be for a minute then suddenly overfill?  If I adjust the float more it won't be set on the dot.  Maybe tighten it up a little to where it's just below the dot and see if it seals?

 

Thoughts?

 

Thanks again for all your help on this guys.

if you have a mechanical pump the pressure can be adjusted. it is located by the carb maybe behind it. If its a stock carb the stock electric pump shouldn't be pushing too much psi. if you really think its flooding check float level and make sure the spring or whatever stops when the fuel reaches center of clear hole on carb works.. If you think the pump is pushing too much psi put a regulator before the carb after the filter. anywhere in between the line will suffice. I DO NOT suggest the mr.gasket one because mine failed and I was tracking it down for months. this will tell you a lot about your fuel system right away and it will be easier to diagnose what to do next. If you havn't already I would replace the fuel filter as it can cause issues itself and is an $8 2 minute job. You might be missing a gasket somewhere if you have fuel dumping out the side of the carb. 

 

 

you can see my thread if you wanna read through it i'm sure you will find some useful information. (chasing down fuel issue 85' z24 weber 32/36)

[Jwalth02]

Well it is not the stock pump, it is the aftermarket facet pump that says 7-9 Pai and I don't know if that is too much or not. And it's got two new filters, the one on the new pump and one in line just before the carb.

 

I just got done pulling the needle seat and cleaned it out, blew out the return line to tank and the line to where it T's, and it's still over filling. I'm gonna give the needle one more shot otherwise check actual fuel pressure.

[captain720]

3-5 psi is what you want I believe, correct me if I'm wrong

[datzenmike]

5 is close enough but 3.5-4 even better.

[captain720]

5 is close enough but 3.5-4 even better.

Yes my 4wd is quite happy at just over 3.5 with regulator

[bottomwatcher]

Add a regulater for that high of pressure pump. I am running the facet 3-4 psi on my pict 34 on my 68 beetle no issues. Good pumps but carbs like 3-4 yours is way too high.

[Jwalth02]

Ok I will look into a regulator, however I did get it to stop over fueling by blowing out the return... Now it idles great got it all adjusted and back together and BAM. Died.

 

Fuel level is still correct, not overflowing anymore just quit.

[Jwalth02]

So tomorrow I have to pull the carb off again.  After checking all of my vacuum lines I got out the carb cleaner and started spraying.  On the back side towards the EGR it is sucking air.  This might be my issue.

[captain720]

So tomorrow I have to pull the carb off again. After checking all of my vacuum lines I got out the carb cleaner and started spraying. On the back side towards the EGR it is sucking air. This might be my issue.

Yes that's an issue for sure especially if intake side of EGR.

[Jwalth02]

This is the best I've ever gotten it to idle, when it first starts it idles normal but then goes to this lope... WTF?

 

It does it with the air cleaner on or off, and I have checked all the vacuum lines three times, no leaks and no sputter with the carb.  The only way to clear it is adjust idle speed past where the idle mix screw makes any difference.  It still drives good kinda sputters if I goose the throttle but if I ease into it it's fine.  Should I even worry about it?

[Jwalth02]

Well I feel like I am beating a dead horse here...

 

I finally had the chance to put a regulator on, the gauge bounces between 4-5 psi while running so I am calling that pretty close.

 

I adjusted the float again and got the fuel to hold steady in the dot in the sight glass.  Idle sounds good while the choke is active, but as soon as it warms up and opens all the way it sounds like it is sucking air through the secondary and goes to sputtering and then either lopes, or dies.

 

Any last suggestions?  Or is there someone out there that wants to take it off my hands...

[datzenmike]

The choke forces an over rich condition which will hide an otherwise lean condition at idle. When the choke comes off the lean condition reasserts itself and the idle quality can drop.

 

I see the engine shakes badly.

 

The idle mixture screw is on the right side of the carb base and set and sealed with a plug at the factory. If you don't have emission checks you can drill a small hole in the plug and start a wood screw into it and pull it out. Now you can use a screw driver to set the mixture and idle speed correctly. This may clear up the poor idle. To set the mixture turn idle down as low as possible. Turn mix screw in and out to find the best smooth idle. Idle speed will probably increase so turn it back down. Repeat as many times as needed until you get the smoothest idle that can't be improved and the idle speed is 750-850 warmed up.

 

Idle mixture screw...

 

Check the plug wires alternate intake, exhaust, intake, exhaust, intake, exhaust... and that the wires go to the correct plugs.....

 

 

Are the valves set for clearance? A tight valve can do this.

 

Next a compression test looking for a low cylinder.

.

[Jwalth02]

Mike, again I really appreciate your help on this, but we have been through all of these steps already.  I have adjusted the idle mix screw and the speed screw so many times they should be wore out.  That is what has gotten me to this point.  As stated in the rest of this whole thread I have made lots of progress as it would not run at all before.  I have triple checked the wiring for the spark plugs, both coils are firing, and the valve lash has been set.  I have the idle (when it runs) sounding good but I cannot tell you the RPM's as the tach does not work.

 

Remember, the truck ran fine before I let it sit for years.  Then changed the fuel pump and this is where I stand.