cleaned carbs, now running wierd...

[stevef1972z]

After a few months, hows the gas smell?

[clindayag1]

Pulling the choke on to get it to run says they are way lean. Run the nozzles full UP and then back them down 2 1/2 turns and see what that does.

Also it may be more busy work rhan anything, especially if you didn't change float levels, but with the nozzles at 2 1/2 turns down and after the car has idled for a bit, you can remove the domes and pistons and look down into the nozzle orifice and see where the static fuel level is in relation to the top of the top of the noxxle. You should see gas within a 1/16" of the top of the nozzle.

Be careful when reinstalling the dome and piston to center the needle without any bind on the nozzle.

yeah i figured they were a bit lean. now im 3 turns down and it runs better now. but now, when i drive i cant go past 3k rpm. if i try, i starts to rumble like its goin to stall, especially when i try to floor it.

[monkeyman]

Have you had a look at your spark plugs? If you find three of them are black and sooty, then the associated carb is running too rich. There has been some confusion about the float settings over the years. In some places/books, the float setting is the same front and back. In other places, this was revised so they were different.

Also, if they fouled before you adjusted everything, they might still be problematic until they are cleaned up.

Have a look at the spark plugs, they might tell you something.

Eric

[clindayag1]

Have you had a look at your spark plugs? If you find three of them are black and sooty, then the associated carb is running too rich. There has been some confusion about the float settings over the years. In some places/books, the float setting is the same front and back. In other places, this was revised so they were different.

Also, if they fouled before you adjusted everything, they might still be problematic until they are cleaned up.

Have a look at the spark plugs, they might tell you something.

Eric

yeah they are all black and sooty except #3 which was kind of oily. i figured they were too rich when turning them 3 full turns down. also i noticed that my oil is pretty dirty and i just changed it a few days ago. could that have something to do with it?

[=Enigma=]

Have you checked to ensure that you are getting adequate duel supply? Check all fuel filters for clogs and rust scale. If you find a lots of rust, you may need to clean your fuel tank. You'll find a fuel filters near the on the right fenderwell, a screen filter in the fuel inlet at the carbs, and if you have a stock electric fuel pump, there's a paper filter element in there as well, and if you or the PO have added any others check those as well.

[monkeyman]

yeah they are all black and sooty except #3 which was kind of oily. i figured they were too rich when turning them 3 full turns down. also i noticed that my oil is pretty dirty and i just changed it a few days ago. could that have something to do with it?

Dirty oil doesn't sound good, but I don't think it will be the cause of the problems you are experiencing.

Oily spark plugs are not good. I don't know if you can do much about it without rebuilding your head or putting new piston rings in. Let's ignore that problem for now (it might turn out that when you get everything running ok, the oil isn't such a problem...).

Sooty spark plugs mean you are running too rich. If you checked them in the morning after driving only five minutes with the choke on, then I wouldn't be surprised to find sooty plugs, so I assume you checked them after running a while.

A couple of things to check:

Are you sure you are setting the floats correctly? How are you setting them?

Did you check that your jets are returning fully to the up position when you release your choke as JZM mentioned above? It would be very unsurprising if they get stuck (so your car continues to run rich when you finish with the choke).

Is your ignition ok? You replaced the rotor and dizzy cap etc. Did you replace the points and condenser as you said you would? Sooty plugs can also be a sign of weak ignition (down the track you might think about a pertronix kit or similar).

It also wouldn't hurt to check that the vacuum advance is working, and that you don't have any vacuum leaks that keep it from working.

But definitely check that your choke is working properly when you switch it off. The jets struggle to get all the way back up when you let the choke out for a couple of reasons:

The build-up around the return spring introduces friction so that it doesn't have enough force to get the jet back up. Also, if by now you (or a previous owner) has changed the fuel hose between the float bowl and jet with one from the general parts shop down the road, you can bet it is thick fuel hose and that it wants to straighten (so it fights the return spring as the jet pulls up). This will definity have the car running too rich. The Nissan fuel hoses are thin and made in a U shape so they don't put any force on the jet. It might seem that having the choke out works because the choke also adjusts the throttle.

And one last thing: give the spark plugs a clean. Starting with sooty plugs is just going to confuse your trouble shooting.

Let us know how you go.

[clindayag1]

Dirty oil doesn't sound good, but I don't think it will be the cause of the problems you are experiencing.

Oily spark plugs are not good. I don't know if you can do much about it without rebuilding your head or putting new piston rings in. Let's ignore that problem for now (it might turn out that when you get everything running ok, the oil isn't such a problem...).

Sooty spark plugs mean you are running too rich. If you checked them in the morning after driving only five minutes with the choke on, then I wouldn't be surprised to find sooty plugs, so I assume you checked them after running a while.

A couple of things to check:

Are you sure you are setting the floats correctly? How are you setting them?

Did you check that your jets are returning fully to the up position when you release your choke as JZM mentioned above? It would be very unsurprising if they get stuck (so your car continues to run rich when you finish with the choke).

Is your ignition ok? You replaced the rotor and dizzy cap etc. Did you replace the points and condenser as you said you would? Sooty plugs can also be a sign of weak ignition (down the track you might think about a pertronix kit or similar).

It also wouldn't hurt to check that the vacuum advance is working, and that you don't have any vacuum leaks that keep it from working.

But definitely check that your choke is working properly when you switch it off. The jets struggle to get all the way back up when you let the choke out for a couple of reasons:

The build-up around the return spring introduces friction so that it doesn't have enough force to get the jet back up. Also, if by now you (or a previous owner) has changed the fuel hose between the float bowl and jet with one from the general parts shop down the road, you can bet it is thick fuel hose and that it wants to straighten (so it fights the return spring as the jet pulls up). This will definity have the car running too rich. The Nissan fuel hoses are thin and made in a U shape so they don't put any force on the jet. It might seem that having the choke out works because the choke also adjusts the throttle.

And one last thing: give the spark plugs a clean. Starting with sooty plugs is just going to confuse your trouble shooting.

Let us know how you go.

i haven't set the floats. i don't know how to do that. i assume they are good because the car ran good a month ago. i changed the cap, rotor, wires, points and condenser. that gave it a little bit of improvement. the vacuum advance is good. all thats left is the choke issue and fuel hose issue.

so how do i check if the choke is running properly? i'm going to check the fuel hoses and let you guys know results. thanks for the help, i really appereciate it;)

[clindayag1]

so far i've checked everything you guys told me to check. i changed the plugs which were sooty. everything else looks good. but when i checked the floats i noticed that the rear float had a significant amount of rust and sediment settled at the bottom. so i cleaned out the float bowls and readjusted the floats. then i took it for a test drive. when driving its starts to struggle after 3k rpm and if i keep it there, the rpms start to decrease even though i try to give it more gas. i also noticed that you can really hear the carbs suck in a lot of air. i think its sucking in too much air because when i try to floor the accelerator it would stall if i didn't let go.

so i guess i'm not getting enough fuel. i think the rust has something to do with it. i'm going to get a new fuel filter and see what that does. besides the fuel tank, is there anything else that i can clean out that might have rust in it?

[Weasel73240Z]

besides the fuel tank, is there anything else that i can clean out that might have rust in it?

Blow out all of the fuel lines.

[Bruce Palmer]

You got the final filters in the float bowl lids cleaned out, correct?

[clindayag1]

so far i've cleaned the float bowls, and the screens that go to the bowls, replaced the fuel filter, and blew air through the fuel lines. unfortunately there has been no improvement. but after sitting in the garage for a couple of weeks and i decided to take it for a spin and see how it does. when i drove it it ran good and the problems went away. how could that be?

[Weasel73240Z]

so far i've cleaned the float bowls, and the screens that go to the bowls, replaced the fuel filter, and blew air through the fuel lines. unfortunately there has been no improvement. but after sitting in the garage for a couple of weeks and i decided to take it for a spin and see how it does. when i drove it it ran good and the problems went away. how could that be?

One guess is that when you blew out the lines, you dislodged a big chuck of crap stuck in a line, or in the fuel pickup in the tank. But as long as said crap remains in the tank, it will likely clog again eventually. Might be time to inspect/refurbish the fuel tank. Just a guess.