Sticking throttle 28 pict carb

[Java beetle 65]

Hi there

I have noticed a problem on my carb in that it idles way too high, the cam doesn't even return fully so adjusting the screw has no effect. If I push the cam in I can get the rpm down but not that much. Impossible to get it to stall. Would this be a worn out spring somewhere, or sticking butterfly valve or a bent cable? There is a 3/4" thick carb spacer to avoid it hitting the generator. Car is RHD so not sure it's an issue at the pedals.

Also... what is the correct method for adjusting volume screw? Seen various different ways. Don't have a tachometer to do it 100% with RPM so just need a foolproof method (like screw out 2 and a half turns from fully in)

At the moment the car idles way too high and blows a lot of black smoke (running rich I presume). Choke is adjusted ok, just slightly open when starting from cold.

Ps carb was rebuilt 2 years ago so isn't worn...

Thanks!
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1965 java green UK beetle
1965 pearl white australian beetle

[runamoc]

Every year driving on the beach the linkage on the carb would become 'stiff', after about 5 days. I just sprayed it with some spray lube and everything was back to smooth.
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VW Wiring = It's just wires

[EverettB]

The "cam" that makes the idle higher when the choke is on needs to be oiled at its rotation points every once in a while.
Try that first if it's sticking.
If the cam is open it's running rich and that could be the black smoke.

On the volume screw, turn it all the way in, then turn it out 1.5 turns to get a starting point. Don't crank it in, just do it until it touches.
Adjust from there.

The car should stall if it's turned in all the way, otherwise the idle circuit is plugged or you have a vacuum leak, usually at the carb. bushing from wear.

One example from the 1961 owner's manual

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[Java beetle 65]

Thanks for the advice.

The cam which the throttle arm rests on when the choke is activated rotates freely. It's the rotation point at the base of the carb which seems to be the issue. Sample image below:

Might pull of the carb and see if the butterfly valve is sticking...

I was hoping it might be a simple problem but maybe not!
_________________
1965 java green UK beetle
1965 pearl white australian beetle

[Cusser]

Question: if you disconnect the accelerator cable, does the arm move freely or does it still hang up??
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[Java beetle 65]

When the accelerator cable is disconnected it goes all the way back. Must be something wrong with the cable? I wonder if the carb spacer has anything to do with it?

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1965 java green UK beetle
1965 pearl white australian beetle

[Java beetle 65]

Tried taking the spring off and pulling the cable reasonably tight. The cable is about 4mm too short to engage with the barrel but. Wonder if it's the carb spacer that is causing this problem?
_________________
1965 java green UK beetle
1965 pearl white australian beetle

[Java beetle 65]

With the carb spacer off the cable is long enough.
_________________
1965 java green UK beetle
1965 pearl white australian beetle

[EverettB]

Why do you have a spacer and can you remove it?
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[Java beetle 65]

Accelerator pump clashes with 12v generator.
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1965 java green UK beetle
1965 pearl white australian beetle

[Java beetle 65]

Think I found the problem

When tightening the throttle cable bolt, the cable would twist sideways making the cable effectively shorter. Managed to hold the bolt in place and this didn't happen as much.

What is the correct setup, is a retaining washer missing?? Mine has loads of free play sideways and can be popped out if pushing on the right side.
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1965 java green UK beetle
1965 pearl white australian beetle

[Cusser]

Personally, I think that the early VW return set ups are a pain the the butt !!! Apparently, VW thought similar and later re-engineered to be like this (photo from gallery)

And can you get a shorter spacer?

If you look carefully at this photo of my ugly but nice running 30-year-old 1835cc engine with a Weber carb below, you can see where I rigged up my own throttle return spring, maybe you want to consider similar since your carb doesn't have the same hardware as the later VW pictured above.

_________________
1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[glutamodo]

Well that re-design of the cable return spring was in tandem with the redesign of the cable and accelerator pedal linkage!

Personally, I've really not had much trouble over the years with the stock cable-mounted return spring, correctly used with the stock style solid-wire throttle cable. But I have had more than one issue with that horrible "Z-bar" pedal linkage... I'm surprised that VW stuck with that not-very-good design for as long as they did (1958 to mid 1966)
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Andy T.


IMAGE NOTE: It has been noted that Chrome based browsers may have issues in displaying my vast image library, which use non-secure links and are on an FTP server. Images should still be viewable if the link is clicked though.
I do not know how to fix this. All I can say is it all works fine for me with what I use, Firefox.

[Cusser]

And remember - the poster is in Australia - so likely has his pedals on the "wrong" side !!!
_________________
1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[glutamodo]

Oh yeah, good reminder, the normal rules kind of go out the window when dealing with them down-under beetles.
_________________
Andy T.


IMAGE NOTE: It has been noted that Chrome based browsers may have issues in displaying my vast image library, which use non-secure links and are on an FTP server. Images should still be viewable if the link is clicked though.
I do not know how to fix this. All I can say is it all works fine for me with what I use, Firefox.

[EverettB]

[vwoldbug]

I think the tube in fan shroud is supposed to be push down flush . We put a hose clamp on the front side of fan shroud to secure it .

[glutamodo]

the tube stays put (thus, no need for any clamps) if you have this style of throttle return spring:

_________________
Andy T.


IMAGE NOTE: It has been noted that Chrome based browsers may have issues in displaying my vast image library, which use non-secure links and are on an FTP server. Images should still be viewable if the link is clicked though.
I do not know how to fix this. All I can say is it all works fine for me with what I use, Firefox.