hesitation and now no start

[scottyrocks]

I have been in a long battle with my bug (stock '63) to get it to stop hesitating, and every time I do something, it either doesn't solve the problem, or something else goes wrong.

I had the car running today, after a carb teardown and cleaning, and there was a hesitation when I hit the gas from idle, which is new.

The original hesitation problem was a random miss that got worse as the car warmed up. The last thing I did, finishing this morning, was a fuel system service, as I thought there might be crap in the bottom of the tank, blocking fuel flow intermittently.

I came inside to have lunch and now the car doesn't start at all. I am completely frustrated and am ready to torch it.

Since I began this fruitless escapade, I have:

- adjusted the valves numerous times
- replaced and/or adjusted the points, condensor, wires, plugs, coil
- took the carb apart and cleaned every opening and moving part except the choke adjuster
- adjusted the idle mixture
- set and reset the timing
- did a front end wiring cleanup so that all the lights now work properly
- cleaned or replaced everything from the tank back to the carb. Tank pulled out and cleaned, metal lines blown out, and all rubber replaced. New filter installed under the tank.

The car started right up after the fuel system service, which I thought odd, as I thought it would take some time for the fuel pump to pull fuel from the tank to the back of the car.

I then drove it around the neighborhood. It had a hesitation off idle after every shift. Idle was very low, which it wasn't before I did the tank and fuel lines.

And now it won't start. Between the car running before lunch and not starting after lunch, I don't know what the fuck to do anymore.
_________________
“If you care for a thing long enough, it takes on a life of its own, doesn't it? Mending old things, preserving them, looking after them – on some level there's no rational grounds for it.”
– D. Tartt, 'The Goldfinch'

[KTPhil]

Carb adjustment is often the last thing to do, after making sure valves and ignition are spot-on. So check those first.

Check the choke adjustment for early or incomplete opening when warm.

I'd use your favorite method of checking for intake leaks, whether spraying fluid at joints or with the "redneck stethoscope" to listen for leaks, probably worst at idle.

When you cleaned the carb, did you make sure the balls rattled free as you shake it? If you hear nothing, they are still gummed up, and your accel pump is probably not working.

Next, with the key off and air cleaner removed, look down the carb and watch for the acceleration pump spray pattern, as you slowly open the throttle all the way. Does it shoot the gap between the carb wall and the opening throttle plate? That's the ideal. If it hits either, grab it with pliers and rotate it until it does. Then gently peen it in place so it won't come loose.

One detail on that accel pump is how you tighten the cover. Loosen all four screws slightly, enough for the diaphragm to move but not wrinkle. Now open the throttle all the way, and while holding it open, tighten the four screws. This process ensures you aren't stretching the rubber diaphragm at full throttle, which can tear it prematurely.

If your main jet is clear, it's time to tweak the idle mixture. Fully warmed up, then rotate it GENTLY clockwise until the idle speed drops, then back out until it is normal again. Lastly, tighten it 1/8 turn or less from that point of first slowing down. Now set the idle speed.

[scottyrocks]

The car started just now so I took a test drive to check the current symptoms.

It ran almost okay for two blocks in the neighborhood. The highway entrance is literally right there so I took the on-ramp.

As soon as I got onto the ramp and hit the gas the car bogged down and spit and backfired. It wouldn't accelerate to highway speed but I had no choice so I merged (thank goodness traffic was light).

I got off at the next exit and worked my way back home. By the time I got back to my neighborhood the car barely ran at anything above idle. Spitting, backfiring, barely any acceleration.

It idles perfectly, though. Smooth as silk.

I will take the carb off and apart again. I didn't know anything about any balls in there. I will shake it and listen for rattling.
_________________
“If you care for a thing long enough, it takes on a life of its own, doesn't it? Mending old things, preserving them, looking after them – on some level there's no rational grounds for it.”
– D. Tartt, 'The Goldfinch'

[Zylinderkopf]

A few things to check:
-is it running on all 4 cylinders? At idle take one plug wire off the distributor at a time and listen ... does the engine slow down? Put it back and pull the next one.
- is the firing order correct ? 1,4,3,2 ...
Follow each plug wire from distributor cap to plug to make sure
-is the timing correct? Which distributor and carb are you running?

Good luck! I’m sure you will get this sorted out!
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1963 Beetle
1966 Beetle 1300
1970 Karmann Ghia Coupe
1971 Super Beetle
1974 Thing


"A lot of people never use their initiative because no one told them to."

[wcfvw69]

Tell us what distributor and carb you're running here?

Your symptoms sound electrical to me. Bad condenser? Does the carb have an electromagnetic fuel shut off solenoid? How are the points? How's the dwell?

What's your fuel pressure too?
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[scottyrocks]

[scottyrocks]

[KTPhil]

[mukluk]

With fuel dripping out around the throttle shaft upon returning from your highway run, I'd suspect your float needle valve is sticking, causing the engine to flood.
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1960 Ragtop w/Semaphores "Inga"

[KTPhil]

Yeah, recent posts suggest the rebuild kits still contain crappy needle valves, and so re-use of the original one is still the recommendation.

[scottyrocks]

[scottyrocks]

[scottyrocks]

[mukluk]

The float needle valve is a pretty simple affair with two parts, the body and the needle valve. In the diagram below you can see the valve assembly screwed into the roof of the float chamber, the body portion which incorporates the valve seat is number four and the needle is number five. Normal operation has fuel coming from the pump into the supply tube, passing through the float valve via the open needle, and filling the float bowl. As the fuel level rises in the float bowl the float rises up until it contacts the end of the needle portion of the float valve, which is then positioned up into contact with the valve seat in the valve body which then cuts off or severely restricts the inflow of fuel. Excessive fuel pressure from the pump can overcome the float valve or the needle can stick in the valve body, leading to overfilling/flooding the float bowl. When checking the float valve, the needle should move freely in the valve body and holding the needle shut with your finger should prevent fuel flow though the valve if you were to briefly crank the engine over to operate the fuel pump.

Adjusting the fuel level in the float bowl is accomplished by varying the thickness of the washer/seal between the float valve and the carburetor top. Checking the fuel level is done by letting the engine run for a sufficient time that the float has opportunity to rise up and close the float valve, the engine is shut off and the carb top is removed, then you measure the distance from the top of the carb body to the fuel level in the bowl. Right offhand I don't have the spec handy for a 28PICT, but hopefully somebody can provide that piece.

A quick note in regards your throttle plate sticking a bit -- overtightening the linkage retaining nuts at either end of the shaft (where you have the arrows pointed in your "fuel dripping here" pic) will often cause the throttle to stick, try loosening them just a bit to see if that frees things up.
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1960 Ragtop w/Semaphores "Inga"

[scottyrocks]

Fantastic explanation and diagram. Thank you.

I remember adjusting float heights on motorcycles which involved removing the carb(s) from the bike, taking off the float bowl, and measuring from the bottom of the carb body to a certain point on the float. If it wasn't right, a tab was bent to bring it into spec.

Today, the first thing I will do is take the carb apart again to see if the float needle is obviously not moving freely. Then I will reassemble and attempt to start the car. If it starts I will do the float height measurement as you described, although I now suspect that the problem is with the valve. I'll know better when I have it in my hands.

If the valve is sticky I will have to get a new one. I was looking at JBugs, as they have a number of rebuild kits. I've read a lot of less than flattering reviews about EMPI stuff. Would one of their carb rebuild kits be okay or should I look at another brand?

I know that fuel pressure should be 2.5 something. How would I measure that?

I will check the throttle plate linkage and loosen it slightly. Hopefully that will free up the plate.

And hopefully someone knows the correct distance for the float measurement and will post it here. In the meantime, I will try to find it elsewhere.
_________________
“If you care for a thing long enough, it takes on a life of its own, doesn't it? Mending old things, preserving them, looking after them – on some level there's no rational grounds for it.”
– D. Tartt, 'The Goldfinch'

[scottyrocks]

I just read in another thread that float height rarely, if ever, changes from original, and problems involving overflowing float bowls are most often the valve sticking or the float become water (fuel) -logged.

While checking the valve I will see if my float still floats.
_________________
“If you care for a thing long enough, it takes on a life of its own, doesn't it? Mending old things, preserving them, looking after them – on some level there's no rational grounds for it.”
– D. Tartt, 'The Goldfinch'

[mukluk]

A poster in the float thread you bumped made an excellent observation that the pin the float pivots on can also be a problem if it causes the float to stick, so that'd be a good thing to check as well.

For carb rebuild kits I've had decent luck with Echlin brand, usually available at Napa Auto. If your float valve is sticking, you may be able to put it back in service after cleaning in solvent and blowing out with compressed air, just be sure to test its operation afterward.

To test your fuel pressure you'll first need a pressure gauge. The one I picked up was fairly inexpensive and not only does it measure fuel pressure in the lower range needed for carbureted engines, but it also can be used to measure vacuum. The main thing to keep in mind when selecting a pressure gauge is to make certain it can measure pressure down in the single digit range -- the majority of fuel pressure gauges you find in stores these days are for fuel injected engines and are quite useless for anything below about 20 pounds of pressure. Make sure your gauge also comes with a T fitting, otherwise you'll need to pick one up separately. Once you have your gauge and T fitting, you'll disconnect the fuel line that runs between the fuel pump and carburetor, insert the T fitting into the car's line and attach short sections of fuel line to the other two parts of the fitting: one line will go the gauge and the other will complete the connection to the pump or carburetor, depending on which end you disconnected. I prefer to disconnect the line at the carb and plumb the gauge in there as it keeps things away from the fan belt a little better, but it's not really important which end you choose so long as the line connections don't leak. With the gauge plumbed in, you'll now start your engine normally and observe the fuel pressure reading on the gauge. The preferred pressure range is about 2-3psi, 4psi is still acceptable in my opinion for a stock carb though a bit high, but higher than that should be adjusted down.
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1960 Ragtop w/Semaphores "Inga"

[scottyrocks]

I have on order a carb rebuild kit from my local NAPA. I don't know that it's Echlin, though. It comes with everything for 28 – 34 Solexes. The main difference between all the models is the top-to-bottom gaskets.

The float pin is straight, and I cleaned and polished it up with some 0000 steel wool. Now if I can get the steel wool into the float's mounting bracket without breaking it I'll be all set.
_________________
“If you care for a thing long enough, it takes on a life of its own, doesn't it? Mending old things, preserving them, looking after them – on some level there's no rational grounds for it.”
– D. Tartt, 'The Goldfinch'

[scottyrocks]

[mukluk]