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Crypty's dead carbs

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Tinster

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Here's a photo of Crypty's non-functional carbs.
Professionally rebuilt by Jeff Palya approximately
225 miles ago. The rear carb gushes gasoline like
an open faucet.

1. Gas tank removed and cleaned spotless inside.
2. 100% new fuel lines and fittings.
3. Five in-line fuel filters
4.New Moss Motors fuel pump

At everyone's request-3 hours this morning:
Carbs removed from car and observed to be spotless
with no crud, sand, rust, silt or spiders. Rear carb
continues to gush gasoline. Needle valves clear and
clicks easily when rotated 180*. Floats rotate smoothly.
No crud of any kind observed anywhere.


I think it would be a total waste of money to have Jeff
rebuilt the carbs again. What are these carbs worth to
sell on E-Bay in an honest as-is condition? Maybe a carb
expert could fix them. I could use the cash toward
purchasing new carbs.

finalconfig.jpg


oldcarbs.jpg
 
Send them back to Palya.

No way should he charge you full freight to fix whatever is wrong - in fact with that sort of mileage on them he'd be smart to do it for a nominal cost...
 
Dale,
Do you know what the fuel line pressure is running? I'm guessing it should be around 1 to 2 PSI or 3PSI at the highest. New carbs won't correct a high pressure problem. You could also test the carbs by switching the floats and needle valves to see if the gushing problem moves to the front carb. Could you switch the infeed fuel line by adding another section of hose? Just some low cost checks for consideration.

Phil
 
Some things to consider...

1. Where is the flood originating? Are the float bowls leaking? Did you use a light smear of grease on the gaskets? Fuel enters at the side and is held in the float bowl; there are not many places it can leak. Are the floats set correctly and floating? Nothing stuck/lodged in the jet?

2. Are your hoses sized corectly and clamped tightly? Often the wrong size hose is used. Looks like you have Aeroquip/Earls hose and AN fittings, are these possibly the source of your leak? Have you tried using just plain old fuel hose?

3. What type of pump are you using? As mentioned, you should not have more than a couple lbs of fuel pressure.

4. I wouldn't throw the towel in on these just yet. Fiddle some more. After that send them back for testing
 
Rather than giving up now, why not at least find out where it's leaking ? Take the bowl off, turn the carb upside down, and use a length of line to blow into the fuel inlet. The weight of the float should be enough to shut off as hard as you can blow. So where it leaks is the problem. If it doesn't leak during this test, then either the fuel pressure is too high, the level is set too high, or the float itself is too heavy (defective).
 
Good test method Randall.

I think that fuel pressure should be checked at this point. Dale may have a fluke pump putting 5-8PSI, which would probably be way too high.

Just a thought, but does anyone think that all of those filters could be creating higher pressure at the carbs? Sort of like a squeeze down on the open garden hose trick?

Volume is volume, but pressure may have been affected, so perhaps it would be good to check it after the pump and then after the filters?

As far as the floats, if Dale takes them off, he could probably measure them on a postal scale to see if that front one is too heavy. It may be porous and have a little gas in it. Rare, but it does happen.
 
I had this problem last year with rebuilt carbs. Wife banished car to backyard shed because of the smell. Couldn't figure out what was wrong, but they were actually dripping out the vent hole you pointed out and was evident in the aircleaner side of the throat.
Took the carbs off this spring-still didn't see a problem. Then I noticed the black spot on the gaskets that sandwich the spacer between the carbs and intake. Noticed that the gaskets are supposed to have a cutout facing to the front side of the carbs, mine didn't (right at the black spot). Replaced with the correct gasket, re-attached, and are now dry as a bone. I think this opening allows air to bypass the throttle plate in conditions where vacuum is very high on intake side of carbs. If blocked, maybe the vacuum pulled fuel from the float bowl? Don't know,but they were wet, now dry.
 
tinster, think toilet tank when working on the floats. Bend the tab up a bit or put another shim washer under the needle valve. assemble,hook up fuel line, plug other line, hold in hand,pull coil wire and have someone crank the engine.Trial and error from here. If it still leaks after several trys,take the bottom off again,hold float up by hand,still leaks...lets float hang down,then hold needle valve shut with your finger.If it leaks then,time for a new valve,...or its leaking past the threads. I do all this myself while smoking,my theory is ....I'm gonna win no matter what...
 
Been putzing with the carbs off and on the car
all morning. Missed my 8:00 AM meeting. Gonna
scoot over to see the client shortly.

Carbs presently back on the car but not tightened down.

I took the carbs off again and took the bottom pieces
apart again. This time, slowly and I measured the float
heights. Dead on at .625".

The rear carb float seemed to not rotate as smoothly
as the front float. I did a minor adjustment of the float
hinge- smoother now. Same as front float.

I blew air thru the needle valves and their threaded
opening.

I'll tighten things up and crank it without the coil this
evening. I checked on the price of 2 new carbs- Yikes!!
$1,600. plus delivery here and 20% excise tax and 15 %
new local tax.

Well, the carbs worked at one time. So they must be fixable.
How much damage could I make in 250 miles or so? Mostly in
short "broke down again" trips of 20 miles or less.

later,

d
 
Question: What is the function of the needle valve?
And what role does the float play?

Just curious to know.

d
 
As I understand them, the needle valve "meters" the amount of fuel introduced into the mix as the tapered end of the needle moves in its bore, and the float regulates the flow of fuel into the carb bowls. Float up closes the flow - bowl is "full".
 
Ok, your making progress now. These carbs were working for 250 miles and not leaking, then the pump broke, crud got everywhere and the carbs started flooding so lets think this out together and figure out what changed.

How about the valves, when you took it apart last time how did you clean them? lets find out if they work properly now. with the carb bottom off, blow into the gas inlet, and with a finger gently push on valve to turn off the gas (or currently air ) flow off. It should be very easy to turn the gas off. `

Now, lift up the float and see if that still turns off the gas flow. If the little tab which pushes up on the gas valve is bent, that also would make it impossible to turn off the gas flow. Check the height at which the floats turn off the gas flow. (while blowing into the gas pipe.)

One other thing, on my junk carb, I see that the gas valve is screwed all the way in, and has an Al washer under it. How is yours installed, is it all the way in, or is it adjustable? maybe it is in to far (missing a washer?) so that the float cant turn it off? did you take the valves out when you cleaned the carbs?


If this doesn't solve it, we will continue.....

Yisrael
 
If you have the carbs off and the bowl removed, with the carbs upside down, the float should measure .75 inches above the carb body at the highest point of the float. That is the measurement for my TR4 so hopefully someone can tell us if that is the same for a TR6 carb. If it measures a lot less than .75 the float may not be shutting off the fuel flow and the tab on the float would need to be bent to achieve the proper float level. You need a manual such as this one on ebay https://cgi.ebay.com/ebaymotors/Haynes-We...136895732QQrdZ1 The workshop manual might even provide the proper float setting.
 
Tinster said:
Question: What is the function of the needle valve? And what role does the float play?
Click to expand...

It gets confusing, because there are two different things that many people (myself included) call "needles".

The "needle valve" is operated by the float, to maintain a constant level of fuel in the float bowl. When the fuel level rises, it lifts the float, which in turn closes the valve, stopping the flow of fuel into the bowl. This would appear to be where your problem is : for some reason the valve is not closing when the bowl is full (or perhaps there is a leak that allows fuel into the bowl even when the valve is closed). The bowl is vented to that port in the face of the carb where the fuel is gushing out.

However, that big brass needle in the center of the carb is the mixture needle, rather than the needle valve. It controls the ratio of fuel mixed with the air admitted to the engine, and is controlled by the air piston under the dome in the top.
 
Tinster said:
This time, slowly and I measured the float
heights. Dead on at .625".
Click to expand...
Although I doubt that's the issue, the information I have is that the float height should be 16 to 17mm, which is .630" to .670".
Tinster said:
I blew air thru the needle valves and their threaded opening.
Click to expand...
But, did you check that lifting the float would shut off the flow of air ?
Tinster said:
Well, the carbs worked at one time. So they must be fixable.
Click to expand...
They are pretty much infinitely fixable, unless you've actually broken a casting or something. That's part of the reason new ones are so expensive, there is so little demand for them. I've got a pair of SU H6 carbs (similar tho not identical to the ZS) with over 300,000 miles on them.
 
Could the diameter of the new 6 million dollar fuel lines have any thing to do with it?
 
That was my point in my question above about all of the filters. I would assume that the new lines are the same ID because they have to fit on the original inlet pipes on the carbs.

And again, I used the word "assume".
 
You need to measure the fuel pressure. A number of folks have suggested this. Have you measured it yet? What was it? If the pressure is too high, the carb cannot stop the flow, the carb will flood and fuel will run all over. I doubt that a rebuilt carb from a reliable source is the problem. There is some history of new pumps putting up way too much pressure.

Bryan
 
Does the float acutal float in some fuel in a bowl. Going back to when I worked on ATVs and motorcycles. Most float will open when the fuel level drops. But there is a pop off press that the float needle should open up. Some where around 6 to 10 PSI. If you blow through the fuel inlet with the float upside down it should not be that hard to make the needle valve open. I realy sounds like the float needle is sticking or the seat is nicked.

Don
 
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