Engine died and won't start, suspecting the Weber 40 IDF

[Stuggi]

Okay, first some back-story. I went to get my Beetle inspected for road safety, and it did the around 4 km stretch without hassle. Then it died when they did the brake inspection and didn't start. When I got it home (on a trailer), I opened filter on my (single) 40 IDF, and it was full of rust fragments and other crap. Suspecting a clogged jet or two I took the top of and disassembled and cleaned all the jets and the float valve and set the float, since it was at 6mm instead of 10mm. After getting it back together, it started fine and I proceeded with adjusting the brakes. After adjusting the brakes, I went for a test drive down the block. I barely made it up and down the street before it crapped out again.
This time I just removed the idle jets and the filter, and after noticing that the filter was clean but the jets completely gunked up, I made a not of disassembling the whole carb and cleaning it.

Today I had it more or less completely apart, and behold, the float bowl was full of crap. I removed all jets, valves and screws, along with the venturis and accelerator pump, and blew through every line with carb cleaner and compressed air. I also pumped through maybe 5 liters of gasoline to clear the lines between the under-tank filter and carb. After reassembly, the car would still not start, so I cleaned the plugs, which were covered with soot, and checked the ignition, and found nothing wrong there as well. After a lot of cranking, I noticed that I didn't get tons of fuel dripping out of the exhaust, and there was no smell of gasoline either. The plugs were dry as well. I then removed the filter on the carb, and gasoline squirted out as if under pressure when I loosened the 19mm bolt. I then removed the membrane for the accelerator pump, and it was as dry as when I assembled it.

So, I'm thinking, stuck needle valve or float, or stuck inlet valve. What should I check, and what could I have missed? I noticed from the diagrams that my carb was missing the washer under the needle valve, I have no clue if I lost it when disassembling the float valve the first time or if there has ever been one there. My carb is a Spanish Weber, made 2002 if I understood the stamp in the bottom of the float bowl right.
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1970 Beetle
1969 Panelvan

Orange VW Fest!
Pulled out of a Lake Fest!

[offrdbus70]

Plugged needle valve i think.
MG[/i]

[Stuggi]

Yeah, but how, it's two part, and I blew it through with carb cleaner. Anyhow, I have a spare one, so I'm gonna swap that in later today. Is there supposed to be a washer under the needle valve on newer IDF's? Cause mine's missing.
_________________
1970 Beetle
1969 Panelvan

Orange VW Fest!
Pulled out of a Lake Fest!

[Itawayoflife]

Sounds like your float valve just needs to be replaced. However, I would just get a gasket kit and clean the carb thoroughly. Then go clean the fuel tank and blow out the fuel lines.
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The quest continues...

[Stuggi]

Hmm, I just cleaned the carb, it didn't help. The tank can't be the problem, since I'm running a brand new filter there. And I blew through the line with air before putting the carb back. I'll try replacing the float valve, now I just have to find out about that washer.
_________________
1970 Beetle
1969 Panelvan

Orange VW Fest!
Pulled out of a Lake Fest!

[modok]

I'm not sure what is complicated about this

You can check the operation of the float and inlet valve pretty easy, if the carb is rightside up, it should be open, if you turn the carb upside down, it should be closed

If you take the lid off the carb you can do the same thing and look at it too

I spose for safety i'll say to use a little hand vac pump to test the valve, but if your vac pump stops working just suck on it and don't inhale



If you put some fuel in the carb with a turkey baster you can run the engine.
If you suspect the needle is glued closed then whatcha do is hit the carb with a mallet first thing to see if that frees it

[Stuggi]

Ok, I'll try that when I get home. Another question, does the inlet valve at the bottom of the float bowl feed all circuits or just the accelerator pump? Cause I'm not getting any gas to the accelerator pump, so I'm wondering if the it's the inlet valve that's sticking. Still, if the float valve is stuck shut then the float bowl would be empty and no gas would get to the inlet valve either.
_________________
1970 Beetle
1969 Panelvan

Orange VW Fest!
Pulled out of a Lake Fest!

[[email protected]]

carb cleaner is not going to clear out rust. Remove your fuel tank and flush it COMPLETELY or you will be doing this every 20min of run time.
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[modok]

ahh, that is a good question

Yes, the little valve at the bottom is the only way fuel goes into the the Acc pump.
I have had that ball get stuck closed a few times, once on a carb where it was not removable. That was tricky. After much thought I hit it really hard with a mallet and that fixed it

But probably the best plan is to take the top off the carb and just observe the float and valves, and make sure they are free and working.

Do you have a respectable fuel filter? At most of the auto parts stores here they have 100 different plastic filters that all fit some kind of car. I just choose the biggest one that will fit. Best filter you can buy for 4$

the built-in filter on the carb does not seem to do much filtering, as you might notice

[Stuggi]

This is quite weird;

This diagram is correct for my carburettor, but the float valve is a one-piece design;

But this older diagram shows the 2-piece design that's installed in my carburettor.

So is the valve wrong for my carb or are they interchangeable?
_________________
1970 Beetle
1969 Panelvan

Orange VW Fest!
Pulled out of a Lake Fest!

[modok]

I believe they are the same, just drawn differently

[66brm]

Yep they just haven't expanded the first drawing
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Aust. RHD 66 Type 1
Aust. RHD 57 Type 1 Oval

[Stuggi]

[Stuggi]

[RailBoy]

Stuggy, not that this is not a controversial practice, but people do and do not like to run fuel filters after the fuel filter but before the carb. If it is set up right, there should not be a problem with getting in the way plus then you have a filter after your lines that are old, plus after the fuel pump just pre-carb.

Also, if you want to run one here, NAPA has 2 Napa Gold Filters available for this that work well, one is like a 1.5" diameter, and the other is like a 2.25" Diameter. Both clear with step fittings.....

Point of why I run one here pre-carb, you can see when it gets dirty, plus it is after the lines and all.. I run two, one at the tank, then one here on my Rail...

Photo for fun: Best Photo I have to Show a Clean Set-Up, note extra fuel line ovder-top of fuel line were it kinda hits throttle return spring hanger.. RB

[Stuggi]

Hmm, I have an adapter right were your filter is to match the pump outlet with the carb inlet, and I'm thinking of rerouteing that line so that it comes up under the generator, over that and behind the carb, so I could also incorporate a filter there. I'm gonna install one on the soft line next to the transaxle today, so I might pick up some extra hose and run a third filter temporary between the pump and carb until all the crud in the last hard line and pump clears out.
_________________
1970 Beetle
1969 Panelvan

Orange VW Fest!
Pulled out of a Lake Fest!

[RailBoy]

This is just me, but I have had two bugs in my early years and my Rail since 1986. Thing is I have found debree in my fuel filter in my engine compartments and not at the tank.. Kinda makes you think..

On my Rail, since it is just free hanging and you can see it I run the big Napa Gold Clear Plastic what ever Fuel Filter right below the tank.. Plus I can keep an eye on it since it is easy to see..

On other cars were they get banged around I run metal filters for safty reasons. Thing is then you can't see into them, so you have to make a practice to swap them out accordingly and often on older vehicles do to rust build up, condensation stuff, deterating what ever, metal fuel lines and rubber hoses..... RB

[Itawayoflife]

[modok]

I ran a big plastic fuel filter between the pump and carb many times.
just have to zip-tie it up away from the cylinder tins and moving parts so it isn't in harms way, and there is little danger as long as you follow common sense

[Stuggi]