Inconsistent idle

You pulled the carb and now there is inconsistency. I'd check for intake leaks first. Intake manifold rubber boots and carburettor to manifold seal. I had a bad one when I did not remove the old carb-to-manifold gasket remains thoroughly. Ran well when cold and choke on and then all irrational when choke flap=20 opened.

I'd check for fuel leaks on the throttle spindle, I've had two carb leak from here making it impossible to set the idle properly. Do you have any warm air going to the carb? Is the carb top on properly? After the engine warms up you can often give the screws a further twist (don't use too much force though)

--Steve

You pulled the carb and now there is inconsistency. I'd check for intake leaks first. Intake manifold rubber boots and carburettor to manifold seal. I had a bad one when I did not remove the old carb-to-manifold gasket remains thoroughly. Ran well when cold and choke on and then all irrational when choke flap opened.

Yeah, I thought of that too, and read some threads on leaks. I did make sure I cleaned the old intake gasket up real well, and the new one seems to make a pretty good seal. The throttle shaft does leak some fuel occasionally, but I sprayed some wd-40 around the area and listened for the engine rpm's to increase, but didn't hear anything. It does wick in there, but wd-40 wicks into most tight areas its sprayed. What does the diaphram and arm do that are attached to the rear end of the choke. There's a little plate on the backside of the carb held on by 3 screws. I changed that diaphram, with a new one from the kit, but something didn't seem to look quite right. What function does that perform, and could a poor install of it cause what I'm explaining?

You pulled the carb and now there is inconsistency. I'd check for intake leaks first. Intake manifold rubber boots and carburettor to manifold seal. I had a bad one when I did not remove the old carb-to-manifold gasket remains thoroughly. Ran well when cold and choke on and then all irrational when choke flap opened.

leaks fuel sometimes, does not suck much air -> float bowl overflowing?

It does wick in there,

the accelerator pump.

No, not that diaphram, the one on the back of the carb, attached to the choke, or is that an accelerator pump too? There's a diaphram with a shaft attached to it that goes into the housing where the choke heat coil is.

I was thinking the float bowl was overflowing too, because it idles and runs VERY rich. Even though the exhaust is aftermarket without mufflers, I can smell super rich exhaust for sure. I just put one spacer on the little shutoff valve when i rebuilt the carb, because I was pretty sure that's the way the old one was. Maybe I should put another spacer in there. To check the float level, I just pull the carb, open it, and look to see how high the level is?

choke pull off. if its not working, engine flods right after it starts cold.

pretty much, yes... be carefull if its hot.

Ok, so I just pulled the carb, and although the level didn't look excessively high, I put the old check valve back in. I cleaned all of the passages again, and made sure everything was super clean. I re-assembled and put it back on. Started it up and I'm getting pretty much the same thing. Even with full choke, its starts right up, but its idling very low, and the motor is shaking back and forth a lot more, and its just not running good at all. It will stay running, but its almost like you can hear every pop coming from each cylinder. I'm kind of at a loss here. Again, the carb is super cold after just a minute of so of idling. Condensation forms on it in just a minute or even less. What would be the cause of this, the carb running too rich or two lean? If the timing is not right, would it cause the carb to get colder than normal? I can't figure why, but thought I would ask. I'm not sure if that is the cause of the very rough idle, or if I should look somewhere else. I did notice the throttle shaft and choke shaft have a good bit of play. I can see that they leak fluid. Would this alone cause a rough idle? Also, what kind of spacer goes between the fast idle cam and the carb housing? Are there washers on both sides of the fast idle cam, on the choke shaft?

first things first... did you adjust the mixture and the idle screws?

if you can see fluid coming out of the shafts, its either gas running down (flodding) or water condensing (weird, but guess its possible)

can you rise the RPMs by pressing the gas pedal? does it backfire? black smoke?

basically if you can get the RPMs up and get black smoke, you are too rich. if pressing the gas pedal gets you a backfire and no smoke, its too lean.

Carb getting cold has nothing to do with it's adjustment. The evaporation of fuel and the expansion of the air while traveling to lower pressure areas (bellow the throttle plate) absorb heat, and this is what makes you carb cold. The heat risers are meant to heat the inlet manifold, not the carb. The carb is heated a bit by the manifold as a side effect. You need warm air to the air filter to prevent the carb from icing. If the carb gets real cold to the point that is starts getting condensations, it will not idle properlly.

Adjust the carb when the engine and carburator are completelly heated, at least after 30 minutes of hard driving, according to the required procedure.

What carb do you have? Has this carb ever been runing properlly in the past on this engine?

Bill, '67 Bug.

The carb is a 28 PICT 1, and yes, it had been running pretty good. I pulled it to clean after I picked up a bad hesitation problem. I cleaned it, adjusted the timing, and swapped out all the old fuel lines. I used a rebuilt kit and changed most of the seals that had a replacement. The carb does not have any hot air going to it. The port on the old air filter was capped off, but it ran fine with it like that. Now, after the rebuild, the carb is noticeably cold, and I think that might be part of the rough idling. I checked the timing again last night and its dead on.

After putting the old check valve in I did not see any gas coming out along the throttle shaft like before. It seems to run rich because I could smell fuel and exhaust much more than before. I can get the rpms to increase, and it doesn't have much of a problem doing that, and only a little black smoke to start. The plugs were pretty black with soot when I pulled them, and there was a lot of soot in the exhaust ports, more than I noticed before. Just seems like rich to me.

You did hook up the choke again, correct? The default position for it is closed (choke on). And you did not by chance use something like a wire or anything else hard to 'clean' the jets, did you? Doing that can open them up and cause a rich condition.

Yeah, the choke is hooked up correct. I adjusted it and its closed when bone cold.

I only used carb & choke cleaner and compressed air, no wires or anything. I examined all of the jets and there are no obstructions or anything like that. I'm pretty sure the float bowl is not overflowing now. I'll have to wait until I can get a good run out of it so I can adjust the carb and get it set the way it should be after this last disassemble.

A leaky float valve could lead to the symptoms you described. By the way, did you adjusted the idle mixture screw or just the throttle positioning screw?

Note:

7.5 static advance should be good for the engine to idle right, but this doesn't mean that timing is correctly adjusted. For the 010 you need a timing light to set the full advance at 3000-3500 rpm to about 30 - 32 degrees BTDC. With the timing light you can also check that your distributor is advancing properly.

Bill, '67 Bug.

One quick question, just let me know if I'm in the ballpark (probably shouldn't use that work when I'm talking timing), but anyway. My pulley has two marks on it, that I assume (oh no, I think I'm setting myself up here) are for tdc and 7.5 deg btdc. The first mark, which is before tdc, is about

1/4" before the tdc mark. Does this sound "about" right.

Because the pulley diameters vary, you can't say much about=20 _about_ 1/4" being about anything in degrees. But, you can find out yourself by measuring the diameter of _your_ pulley and=20 the amount the mark is before the TDC in your pulley. Then do the following math:

360 * mark_from_TDC advance in degrees =3D -------------------------------- PI * pulley_diameter

No one's mentioned fuel pressure yet. Before I put in an electric pump (first one was a facet, I can not recommend it), how well the engine ran, changed day to day. After replacing the mechanical with an electric, stability was found.

I think I have enough fuel pressure. In fact, on a test drive over lunch, I could smell a lot of fuel while on the drive. It was also stalling every time I'd pull up to a stop. I would have to tap the gas pedal to keep it from totally shutting off. When I pulled in the driveway, I looked back by the carb, because its the main thing I've been rebuilding/adjusting, and there was a good bit of fuel on the throttle lever, and I could see some dripping off the bottom of the lever. There was a good wet spot of fuel coming from both sides of the throttle shaft, on both ends of the arm. Should I stop right here and look for a new carb? Am I fighting a battle I can't win without a good carb to start with? I got it idling pretty good before going on the test drive, but it wasn't running perfect when I accelerated, and stalling when I stopped.

"Steve Gift" wrote

Stock pulley? ... and by "marks" do you mean notches on the forward rim? If so, the "about 1/4" " sounds to me like a 7.5 & 10 deg BTDC pulley.

This page might help:

Also: ?p=199930&highlight=notch+dimple#199930 hth

Wow, thanks Scott. This may really mean something. Yes, the notches are on the forward rim, and look like a "V" that would've come with it from the factory. Like I said, 2 of them about 1/4" apart. On the rearward half of the pulley, some PO pull a scratch mark at the first of the two marks. I was *assuming* this was tdc, and the mark to the right of that was 7.5 btdc. Damn, the more I'm looking at those links you sent the more I'm thinking I'm set up now to be 10deg btdc, maybe slightly more, static!! My dizzy, the

010, says 7.5 btdc static. Now I'm thinking the PO put that scratch mark on the pulley to mark where he/she was supposed to time it at, static, so they would remember which mark was the correct one. Lets hope this fixes at least most of the idling and poor performance problems I've having.