Zenith carbs hunting for idle and stalling in gear

[muleears]

Originally Posted by JMela

Inverted cool whip container fits the Zenith tops perfectly.

Genius!


I don't detect any wobble in the cam mech. I will check/lube the vacuum advance today and see if there is any improvement.

Thanks guy for all the advice, this is a really nice car and I'm trying to refresh it properly.

While I'm under the hood, anyone know how difficult it is to replace the steering coupler? Mine has significant slack. I have one for it, just don't want to take it apart and not be able to get it back together!

[Chas H]

It's been decades since I changed a steering joint, but I sorta remember removing all but one bolt holding the steering box and loosening that remaining bolt so the box could be rotated enough to change the joint.

[muleears]

Originally Posted by Chas H

It's been decades since I changed a steering joint, but I sorta remember removing all but one bolt holding the steering box and loosening that remaining bolt so the box could be rotated enough to change the joint.

Just to be sure the attached pic is the part I'm talking about. It only has two hex heads on it. Looks like one end holds the steering shaft(?) from the steering wheel and the other the shaft(?) that goes to the steering box.

[Chas H]

Originally Posted by muleears

Just to be sure the attached pic is the part I'm talking about. It only has two hex heads on it. Looks like one end holds the steering shaft(?) from the steering wheel and the other the shaft(?) that goes to the steering box.

That's the part I remember. I don't remember which bolt holding the steering box to leave in place. That should become obvious when you start the work.

[barry123400]

Spray wd 40 around the bases of the carbs to determine if air leakages exist.If the idle stabilizer seems to be working I would clean the carbs out using laquer thinner.

Just feed it as fuel through the carbs. Dissolves stubborn dried out gas residue really fast. I break the fuel line under the drivers footwell area and feed the carbs from a quart can. Let the carbs sit and soak for twenty minutes and restart. The engine runs just fine on the laquer thinner.

I originally went with this years ago as the idle passages where not flowing..The ideal of removing soaking and kitting the carbs left something to be desired as well as disturbing the base gaskets.

Worked out fine. It may not cure your problem but it will clean up those internal carb passages. Any major difference in them running after cleaning was the residue removal.

Right now you have no real ideal of whats in or not in those carbs. When these carbs sit around unused the gas dries out and the reidue is not easily put into solution again with just gasoline.

[muleears]

Originally Posted by barry123400

Spray wd 40 around the bases of the carbs to determine if air leakages exist.If the idle stabilizer seems to be working I would clean the carbs out using laquer thinner.

Just feed it as fuel through the carbs. Dissolves stubborn dried out gas residue really fast. I break the fuel line under the drivers footwell area and feed the carbs from a quart can. Let the carbs sit and soak for twenty minutes and restart. The engine runs just fine on the laquer thinner.

I originally went with this years ago as the idle passages where not flowing..The ideal of removing soaking and kitting the carbs left something to be desired as well as disturbing the base gaskets.

Worked out fine. It may not cure your problem but it will clean up those internal carb passages. Any major difference in them running after cleaning was the residue removal.

Right now you have no real ideal of whats in or not in those carbs. When these carbs sit around unused the gas dries out and the reidue is not easily put into solution again with just gasoline.

What about running it on straight Seafoam or some other carb. cleaning product? I have sprayed them liberally with carb cleaner inside and out, but I wonder what's in the float bowls and so on.

[RadioTek]

Originally Posted by muleears

While I'm under the hood, anyone know how difficult it is to replace the steering coupler? Mine has significant slack. I have one for it, just don't want to take it apart and not be able to get it back together!

You might be able to remove the steering wheel, the turn signal switch, some of the bolts under the wheel, and a clip ring to get the shaft loose so that you don't have to do the steering box. I have a 107, and that is what I tried to do. Make sure that the sockets of the Allen head bolts on the coupler are COMPLETELY clean before trying to loosen them. I had one that wasn't, and ended up rounding it out, then breaking an easy-out off in it. I still wake up screaming some nights.

The bolts that hold the coupler to the shaft have to be completely removed, not just loosened, before you can get the coupler off. They fit into a groove on the steering shaft and gearbox shaft. Make sure to index your steering wheel, the steering shaft, and the gearbox shaft exactly. This is so you get everything back in place precisely aligned, otherwise you won't have your turn signals cancel properly.

There is a Wikihow for the 107 that I would recommend looking over before starting, to get an idea of what to watch for. Although you will have more room to work with, so things should go smoother.

Best wishes,
Scott

[barry123400]

Originally Posted by muleears

What about running it on straight Seafoam or some other carb. cleaning product? I have sprayed them liberally with carb cleaner inside and out, but I wonder what's in the float bowls and so on.

I suspect a lot of carb cleaners are composed of a good portion of laquer thinner as well. The passages you want to clean can only be dealt with by feeding the carbs from the fuel line. Or filling the float chamber with a small hose and funnel. After they are run dry. Remember again the engine seems to run well on the laquer thinner.

I limit the soak period to twenty minutes just out of caution for the floats. Why I like straight laquer thinner is it is very active on the gas residue breaking it up fast by dissolving it if there.

A quick test I used to preform on old zeniths that had been sitting was to remove the idle adjustment screws. A clean carb will pour fuel out of those points. Most either just dribbled or the passages where totally obstructed with the gas residue. It almost always made a difference after the laquer thinner treatment.

[muleears]

Originally Posted by barry123400

A quick test I used to preform on old zeniths that had been sitting was to remove the idle adjustment screws. A clean carb will pour fuel out of those points. Most either just dribbled or the passages where totally obstructed with the gas residue. It almost always made a difference after the laquer thinner treatment.

Can you tell me where the idle adjustment screws are located?

[dobrodan]

Here's a pic of the tool(s) I made. I just used a 4" CI to PVC adapter and put a piece of laminate with a hole in it in the groove. It fits perfectly over the Zenith and you can even tighten it up if you want to. You should make two of them and just move the Unisyn from one carb to the other. It is really critical that the timing is right on and the bench adjustments are right. I have found that most of these carbs are really screwed up by people who don't umderstand them.

[dobrodan]

Here's a link to the manual for the carbs. It's for BMW, but nearly identical.
http://www.jaimekop.com/CarbManual/Page01/toc.html