idle jets

[mik]

I am going to attempt to remove and clean the idle jets on my '69 124. Are there any suggestions or tips to do this? Are there hidden springs that are going to pop out when I remove the screws? Just want to be prepared for what may come up? Thanks, Mik

[majicwrench]

Tis easy. You are refering to the ones on the side of the carb?? As long as you don't drop them, there is almost nothing difficult. Work on a clean surface. Are you having idle issues??
Keith

[azruss]

These jets are 2 piece. In some cases, you can pull the screw and actually leave the jet in the carb. Also primary and secondary side are not the same, so dont mix them up.

[mik]

The idle has gotten better, was having a hard time, after allowing the motor to run for awhile, keeping it running with the choke pushed in. I did put the magic in the gas tank which has probably cleaned things up a bit. I can get it to idle at around the 800-900 level without having it kill. If I push the choke all the way in, may stay started, but would be very rough. The magic is an additive, and I forget the name, but is in a post response somewhere. I will be getting more of it.

[sptcoupe]

Have you checked/adjusted the idle mixture? And the ignition timing?

[majicwrench]

Putting "magic" your gas tank is not the answer.

[mik]

I have not checked idle mixture or ignition timing. Can you give me a good direction on idle mixture. Do I fully turn the idle screw in and back it out so many turns? It is a 1969 124AS all original. Everything on it, is from the day I bought it 40 yrs ago. I used to do my own work on the car many years ago, but have become very unsure of myself after so many years of storage and not keeping up. This forum has given me alot of great help and the encouragement to started doing my own work again. Thanks for the help, Mik

[sptcoupe]

For the idle mixture, first warm the car up until it has gone through one heat cycle (or just drive it for a few mniutes).

Once the carb body is warm, turn the motor off and turn the idle mixture screw in all the way (clockwise) until it is lightly seated, then turn it out 1 1/2 turns, and start the engine. It should start OK if your jets are the the right size.

With the motor idling, begin to SLOWLY turn the idle mixture screw in. This will lean out the mixture. Within a half to one full turn of the idle mixture screw, the engine idle should smooth out and the idle speed increase. Keep turning the screw in until the engine begins to run rough again and stop. From the point that the engine just begins to run rough, back the screw out until it just smooths out again, and from that point, turn it our 1/8 turn more.

If you turn the idle mixture screw in and the idle does not change or gets worse as you go in, then turn the idle mixture screw in unitl it is ligytly seated and back it out 1 1/2 turns again. From there, begin to SLOWLY turn it out (counter-clockwise). This will make the mixture richer. Within a half turn or so, the engine should smooth out. If this is the case, then from the pint the engine just begines to run smoother, continue to turn it out another 1/8 turn.

If you are moving the idle mixture screw in and out and nothing changes, then the jets are not the right size.

Before you do this procesure, be sure you're timing is correct, you have good plugs and good plug wires.

Let us know what happens.

[majicwrench]

Very good advice above, but I will add, that if moving the idle mix screw in and out and nothing changes, the most common reason is because the jets are plugged. If the carb is all original as you say, do not go changing the jets.

[sptcoupe]

I thought he had already cleaned the idle jets? Could also be a dirty fuel filter, etc etc. We'll just have to chase it down.

[131]

I thought he had already cleaned the idle jets? Could also be a dirty fuel filter, etc etc. We'll just have to chase it down.

When I first put twin IDFs on my previous 131 it continuously blocked idle jets, so much that I kept a screwdriver in the ashtray. When it played up I'd simply pull over, quickly clean jets and continue on. It took a couple of weeks, a few filters and a few tanks of fuel before it settled down.

[majicwrench]

My 72 clogged em all the time, sometimes within minutes of cleaning, till I sealed the tanks and flushed the lines. Methinks fuel filters are really not all that good. Anyway, even after sealing tank/flushing lines, it is an issue every great while. Esp after sitting over the winter. I'm good at cleaning em

[sptcoupe]

It doesn't take much dirt to clog an idle jet. I have used the fuel fiter for a 1973 Datsun 240Z as the in-line filter for years, and if the tank is reasonably clean, it will all but eliminate clogged idles. It is big, and was made for the Datsun's FI system, which means it filters much smaller particles than the average filter on the market. Dirt in the venturis that comes form poor sealing around the air cleaners can also end up in the idles and the idle breather hole, so dirt doesn't always originate in the gas. Old or cheap fuel lines can also begin to flake off small particles from inside the lines that are downstream of the filter and do this in a relatively short time, even though the line looks fine form the outside.

I have recommended that Datsun filter for years, so if you have sealed the fuel tank and are still getting clogged idles, try one. I usually mount a filter upstream of the fuel pressure regulator and fuel pressure gauge unit, and one downtream, before the carb inlet. Also change the fuel lines regularly.

But never leave home without your favorite idle jet remover screwdriver!