My car has been running pretty darn good.It seems to still have a rich smell.Any driving that I have done has been short runs ,to work and back about 5 miles,joy ride 10 miles.Today out to my brothers about a 30 mile round trip.It was running good on the way out.The car sat for about 3 hrs before I left. On the way home after going through a couple of car lots at idle.When I went back to normal driving,it started to cut out.Sitting at a light to long will also put it in the same funk.It seems like when I try and lean it up it just gets worse.like I said I smell fuel so I know it is to rich.But it seems to run the best at this setting.But now I have the cutting out problem to deal with.I believe because it has been sitting for some time now,that if I go drive it it will run fine until I run it to long at low rpms.or at idle...:stupid:

Have you pulled all six plugs and inspected? Have you ran a compression test - what is your oil comsumption?

Are we talking carbs or fuel injection here? Like Mitch stated above, the spark plugs are your window to the air:fuel mixture.

Start with simple things, like a clean airfilter (yes a dirty airfilter causes the mixture to go rich) and fresh plugs. Make sure that your timing is correct. If you have carbs make sure your floats are at the proper height. Also make sure that your nozzles are returning to their full up position with the choke disengaged.

When was the last time you checked the valve lash?

Love to help you with all the vast wealth of experience from this site but....

WE NEED MORE INFORMATION

I POSTED A REPLY TO THIS TREAD BUT NOW ITS GONE...CANT FIGURE THAT ONE OUT.IM ON LUNCH,IL HAVE TO TRY BACK LATER:ermm:

That's strange, my second reply is gone too. I asked where you were in Illinois since i travel there often to Salem Illinois.

Best advice given is to pull the sparkplugs to start the process of elimination.

Madkaw,dont know whats up with the last post,s?? I will try again to sum it up.I am in Rockford.And if I cant get this on my own,I just might take you up on your offer.The car has a crane cams fireballxr700 ignition.This was on it when I got it,dont know if that is good or bad.The one other thing that I had done,after putting on the rebuilt carbs,was to zip tie and tape the wires off of the fireball and from the coil together,to make it look better.last night I put wire covers over them to make it look neat and tidy.well it wouldnt start.So I undid every thing,and it started.So I know something is wrong with that mess.I also found that the wire that goes to the heat sensor in the block has a crack in it.I took it for a ride,and it run out very good.When it got hot,it started missing again.And I did take out the plugs,and they all have a light brown look to them.Here are some pics if it will help.Like I said last night in the post that disappeared mysteriously....If I cant get this motor to run right....I drop a v8 in it over the winter LOL

Segdoh,

Like I said above;

1. Inspect the condition of the spark plugs (post a picture)

2. Check your timing

3. Check your float height (I know you have rebuilt carbs, but the floats can change in shipping)

4. Confirm that the nozzles reseat in the full up position.

5. Reset the mixture screws

6. Check the valve lash

Inspecting old plugs for mixture problems can be difficult. He's a good way to check the plugs:

Put 6 fresh plugs in the car. Start the engine and take it out for a ride. Take a spark plug wrench with you. When the engine begins to run poorly, pull into a parking lot and remove the plugs for inspection. You might even consider checking them when the engine is running well so you have a reference point for comparison.

Matt,

Sounds to me like you have wiring issues rather than carb issues. Put the wrap on and it wouldn't start? Took it off and it would start? Hard to lay that at the feet of the carbs. I'm thinking it's time to own up and start chasing electrical gremlins. Good luck

PS: I'll bet that gas smell is more pronounced when the tank is near full? Old vent lines would more than likely be your culprit there, and they are inside the car.

Edited August 12, 201014 yr by Bruce Palmer

I think Bruce hit the nail on the head, I'll bet you find a loose lead wire on your dizzy, or a bare wire somewhere . I had this same thing happen on my first Z car. I was stranded on a side of a mountain in PA in the winter(10 degrees) and I hought it was those damn carbs. After breaking the tang that supports the float pin in the float bowl and repairing it will safety wire, and after getting frost bite from being in a parking lot doing all this -I had it towed to a shop. The mechanic there-who really appreciated my resto on my Z- found the problem in minutes. Loose wire on the dizzy:stupid:

Unless it's blatantly obvious, I don't blame the carbs anymore.

And Rockford ill isn't close to where I go.

I would, were it me, go looking for a shop proficient in auto electrical systems and have everything chased front to back top to bottom. Datsuns of any model are not that sophisticated. Spend the money, have it done right. It's time........

Crawled under my z today to check out my fuel lines.I found that the electric fuel pump was disconnected and by-passed.I checked it and it is no good.My question is.Is it supposed to have a mechanical fuel pump and electric??