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water choke revisited

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lclark0624

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Well, still no go. Can't get past 2500 rpm and 20 mph on a hill in 2nd.

I took off the breather and the spring/heat body, and plugged the two hoses that connect to the heat body

Then I wired the choke closed and started the engine. Started right up. Idled it until it was at runnung temperature with choke closed.

I released the wire and held the choke closed while I fed the fuel. As I opened the choke, I added fuel. It acted just like it does on the hill - no power and no more than 2500 rpm's.

Just to be sure, I manually lifted the choke in the intake and it acted the same way.

Am I missing something here, or is it time to leave the choke and look again at the ignition system?

lclark0624 /ubbthreads/images/graemlins/driving.gif
 
How's the diaphram in the carb? I'd check to see if it's worn or torn. They're relatively easy to check just by taking the cover off of the dash pot. And yeah, it won't hurt to double check the ignition system.
 
Out of curiosity have you made any mods to your intake or have tried driving with out the air cleaner on while your trying to figure this out? The ZS carb seems to be ultra touchy about the amount of air it gets.
 
IMHO: The first thing would be to get a manual, a rebuild kit and go right through the carb. Rebuild kit is not horribly expensive and all components would be new. For all the faffin' about you have done/could do yet, the thing could be eliminated as a source of the problem and hold no more mystery for you. The mixture adjusting tool helps, but a (IIRC) 3mm Allen wrench and your thumb to "pin" the piston to keep it from rotating and stressing the diaphragm works too... A manual choke kit would be another thing to reduce complexity. In short: Outsmart th' bugger. Take it back to "factory default" settings and know what you've got. If the problem persists, you know what it's NOT, 'cause your carb is as good as new.
 
I threw the damned water choke away installed a manual one and never looked back. The manual choke works like a treat..
 
[ QUOTE ]
I threw the damned water choke away installed a manual one and never looked back. The manual choke works like a treat..

[/ QUOTE ]

Consider your self lucky you can install a manual choke where you live. But in California as part of the under the bonnet visual inspection they check for the water choke during the emissions test. So while some smog techs might miss this – you’re rolling the dice if you remove it because that could cause you fail the test.

Regarding Clark’s possible "choke" problem – If I understand the problem if you bypass the choke manually it runs ok until you release it?

If so I would do as has been suggested and use a manual to go through the step by step choke setup procedure. The ZS Water Choke (enrichment device) is a bit of a mystery to most of us and if things ain’t done just right (or reasonably so) you will never get the carb to run right. But mine would only give me problems when I started the vehicle not after it warmed up. So I suspect you have something else going on.

Vacuum leak, float or a fuel delivery issue perhaps?
 
Thanks for the suggestions.

Nunyas, Guess I'll open the dash pot and check the diafram and then go through the ignition system one more time.

Stewart, I've made no mods to the intake. Yes I drove without the air cleaner and got the same response.

DrEntropy, the manuals I ordered are still enroute by snail mail, I guess. I may just "bite the bullet" and order a rebuild kit using the two downloads you guys suggested in the other string. I did get an adjusting tool in a previous order so I'm set there.

By the way, being a "75 I can put in a manual choke because it's exempt from smog requirements. But, if my hand manipulation of the choke mechanism doesn't do the job and get over 2500 rpm's will a manual choke succeed?

You know the thing that gets me is that all was working like a clock until the brake job. We stopped at the bank and then out of the blue, my wife turned to me and said, "Is the brake on? I have to put my foot through the floorboard to get going." That was the start of the problem.

I still wonder if the mechanic "messed" with something.
 
Check out this article. It demystifies the ever frustrating water choke.

https://www.paulbunyan.net/~jasko/choke/

The guy that wrote this article should be given the Victoria's Cross or something.

Also, I had a mysterious loss of power that I could not figure out. It turned out to be a vaccuum leak at the flange gasket.

morris
 
Great,

Paul's article was one of the one I was refering to above. It is good and clear. I think I'll use it for the rebuild if I go that way.

I will definately look for a vaccuum leak.
 
regarding the brake job...

Never underestimate the power of coincidence....

But then again.

Let me throw something out here for you guys to chew on. This is a '75 B. Doesn't it have a brake servo?

I hate to send him down another primrose path but.....

Could brake fluid leak out of the servo and get sucked into the manifold from the vacuum hose?

Is the vacuum hose connected to the servo and not leaking (hence your suspected vaccuum leak) ???

How about spraying some carb cleaner all around the carbs, vaccuum hoses, brake servo, intake manifold, etc. while the car is running? If the idle changes you have a leak.
 
Good suggestion. I believe the 75B has a brake servo. But I can't see brake fluid getting into it. However it seems logical to check for a leak of the brake power assist hose when checking for any vacuum leaks.

I would also look at the emissions hoses from the manifold to the gulp valve. The 90 elbow is a pressed fitting and can leak. I used some liquid gasket to make a bead around mine before re-inserting it.
 
Fuel filter should be on the fire wall of the engine bay just above drivers foot well. If it ain't jumping out at you try following the fuel line back.

As for the fuel pump it is located just on the inside of the passenger side rear wheel well. Actually protrudes into the trunk. Again follow the fuel line from the gas tank sending unit and it should lead ya right to it.

Good luck,
 
Yup, 75 has a brake servo. Vacuum leak could be the cause, but if you are still getting 'wet' plugs that would seem to indicate a richness problem and not a lean problem from a vacuum leak. Assuming that a vacuum leak would be sucking air into the manifold. I tend to lean (no pun intended) toward the brake job being more consequential than causal, unless the mechanic messed with some of the emissions plumbing or something. Perchance you could ask him?

As for the choke, try driving the car with the choke full off. As long as its not COLD out, you shouldn't need the choke on anyway. Wire or tape the pin that goes into the spring all the way toward the engine (choke completely off) warm up the car, and try driving again. After that, if you are still having problems, then you should pull the plugs and take a look at them and see if they are still wet. I'd also go through the ignition system, it's amazing what a set of bad plug wires will do to a car.

-D.
 
Ok, I wired the choke closed, ran it up to a good temp and then drove it. No change, so I pulled the plugs and ran the plug wire tester again. Lights aglow all the way.

I'm through with the carb. I'm convienced it ignition now.

Did someone say in the previous thread that the distributor center post should not move up and down? If that's the case, I have some movement (1/4"). Could this cause the improper ignition of the fuel?
 
OK. Since this is a crazy problem let me ask a crazy question.

Are you SURE... I MEAN REALLY REALLY SURE... that the spark plug wires are going to the right plugs?

Firing order is 1-3-4-2. Watch the dizzy spin (or your rotor might have an arrow showing rotation) and make sure that the wires are going to 1-3-4-2.

If you get the "right" combination of the "wrong" order it will run but it will feel like it has absolutely no balls at all as you describe (don't ask me how I know).

Doesn't explain the smoke really but what the heck. It's a quick easy thing to check.
 
yip, 1,3,4,2 on the rotation. Someone numbered the plug end of the wires, so it was easy to trace them.

Good irea though to check the simple things.
 
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