1980 z-motor 510 stalling, suggestions?

[pdp8]

Symptom is this, car runs great when it's cold but as soon as it warms up it idles strong but dies when you give it throttle.  It's particularly bad when you come off the brakes and try to start moving after a stop.  I did kit the carburettor since the accelerator pump wasn't working, it wasn't that dirty  at all and I took pains to make sure I blew out every passage with compressed air.

I did find the main venturi to be loose so replaced the O-ring and tightened it in.  If you accelerate *very* slowly you can get up to some sort of speed. 

Automatic and factory carb.  Hose routing looks stock but not sure things are working as they should be.

[datzenmike]

The '80 A10 (or HL510) has an L series engine not a Z. If the carburetor is on the left or driver's side it's an L. The '81 A10s had Z series engines.

 

Sounds like lack of fuel when using the primary barrel. This is somewhat supported by it running better with the choke on which makes the mixture richer. Once the choke is off the engine runs lean. Did you remove the primary jet and make sure it's clear. It's very common for dirt to partly block it.

 

If you can take for a 20 min drive and pull over and remove the plugs and inspect the porcelain insulator tips.

Black sooty and dry is running too rich.

Light tan/creamy is just about right.

Very light or shiny white is dangerously lean.

[pdp8]

The carb is on the passenger side and the valve cover says NissanZ, so I'm thinking Z...  Pink slip says 1980 but VIN starts with WHLA10.  Newer than any Datto I've ever owned so I'm in new territory here.

 

When I ran it in the driveway and looked down the carb, slowly revving it I do see fuel coming out of the primary venturi but you raise a good point in that one of the only orifices I didn't verify was the primary jet.  My smog machine suggests the HCs go really high before it dies like it's dumping fuel, but of course that's completely inconsistent with running pretty well until the choke opens.  Made me question the ignition but honestly I'm a little bit intimidated by anything that drives 8 spark-plugs  using 2 coils!

[datzenmike]

W is Nissan for wagon.

 

Check driver's door jam tag for the chassis build date. If someone swapped the engine they would also have to swap the transmission. An '80 model year begins around June of the previous year. So 6th month of '79 through 6th month of '80. From July '80 on would be an '81 model year. Not that important. If it's a Z20 then it's a Z20. Look between the two exhayst pipes where the dip stick is. On the top edge of the block, just below the head is the engine ID.

 

The primary barrel is the one with the choke plate on it. The primary jet is below it under the float chamber and access is under a 12mm plug on the outside. It's much easier if you remove the carburetor.

 

 

This carburetor is upside down so the secondary is uncovered. You may have to grind down a screwdriver to get the correct width and fit up inside. Jets are numbered with the primary always smaller than the secondary. They will interchange so avoid having both out at the same time. A speck of dirt will reduce fuel flow and cause the engine to run lean.

 

Did you remove a spark plug and look at the color of the porcelain tip????

 

 

[4perrev]

Rich problems get worst with heat. If the carb is not jet right, could be the problem.  Did you check the float height also?  Could be the starting and stopping issue where fuel is rolling over as in a flooding condition.  The float needle could have a groove in it which not allow the float to stop excess fuel in the bowl, same flooding condition.  Common in old carbs.  Just a couple ideas.

[pdp8]

Thanks for the suggestions.

I did replace the needle and seat and set the float height, fuel level looks OK.

I passed the car on to someone more excited about it than I was.

Now I can get back to work on my 210 and the new (to me) 1200.

[vicdat]

Good move PD...stick with the '75's and older here in Cali....