Hi,
I'm still having some minor issues with "Olive", my Superbug, specifically getting her to idle properly.
The car runs great at anything but idle. It accelerates well and will sit on 110km/h no problems. But after the choke cuts out it idles quite rough and will sometimes stall without apparent warning. The problem is worse on a cold day, especially after a doing 70km/h+ for a minute or two and then stopping at an intersection.
The idle seems to increase and decrease at random and I get the occasional "choof" of a misfire through the tailpipe. Increasing the idle to about 1200-1500rpm (estimated) stops the problem.
It's a stock (AFAIK) 1600 twin port with a new electronic SVDA dizzy, new leads, plugs etc. The valves have been adjusted and the air filter is new. Coil is old and the carby (34pict?) has recently been cleaned out professionally. All vaccum lines and hoses appear to be in place and the rubber boots at both ends of the manifold centre-piece seem tight and leak-free. The engine is mechanically spot-on with good even compression.
This is my first air-cooled VW, and I don't yet have a relevant workshop manual. Only the "Keep Your VW Alive" book. But I have owned and worked on countless older cars myself and completed full restorations. So I'm certainly not afraid of getting my hands dirty.
On the dizzy side of the carb there is an appox 10mm flat-head screw. Is this the mixture screw or an air bleed for the mixture. Adjusting it 1/4 to 1/2 a turn either way does not seem to improve the idle. There is also a smaller screw below that which I have not touched. Is that the mixture or access to the jet?
My thoughts:
- vacuum leak? Likely places?
- float valve problem (no petrol spewing anywhere)?
- floating dirt in idle passages of carb?
- mixture?
- idle stop solenoid oscillating?
- carb icing?
- duff plug?
I'm tempted to toss the carb and fit a downdraught weber or similar, as they are very familiar territory to me. But it seems overkill when it may be something small or unrelated.
Advice would be appreciated. 🙂
Thanks,
Brett.
Brett Nicholson
Melbourne, Victoria
1974 VW Superbug L - Olive 😎
1971 Morris Mini Moke - Mopoke
1966 Austin Mini - Audrey
1965 Morris Mini Traveller - Trixie
2007 Land Rover Freelander 2
2009 Nissan Pathfinder
(assuming you have no leaks)
maybe
try spark first take out spark lead from dizzy one at a time and put it back in see if there's any difference for each plug
actually leave it idling, turn it off and see what the plug colors are like
clean carby again make sure every settings are right, blow the passages with compressed air, clean your hands before you put it together (i didn't lol)
call your old man explain the situation, become his assistance for about 10 minutes. go back in the house have a cup of tea
wait til you hear a smooth idle
and that's how i fix my carby problem which turned out to be a fouled plug which turns out to be my mower plug that some how got mixed in 😁
"The idle seems to increase and decrease at random"
That is telling me a vacuum leak is 99.9% chance of being the problem
spray liberal amounts of WD40 around
* carb bushings
* manifold joints
* rubber boots
The Pict's wear out the bushings and you get a wear/leak that "looks" ok
Do the above spray check.
Get your carb rebuilt/bushed and it will be 10 x better
Barry
Futue te ipsum!!!
if you cant find any vac leaks 2 other problems that can give those symptoms is the preheat manifold clogged with carbon or the old 34pict3 overtightened idle jet is a common one
I'd say it's an air leak too - had exactly the same issue on mine when it has standard carb. If it all looks good on the rubber boots and carby it will be the head/manifold gasket. Bit of a pain to change, which is why a mechanic will ignore it.
this might help it sounds like the pilot jet/ fuel solenoid
Keeping it real !
1
Fillister head screw and lock washer (upper body (5)
23
Accelerator pump diaphram spring
2
Spring washer
24*
Accelerator pump diaphram
3
Carburetor upper part
25
Cotter pin
4*
Float valve washer
26
1-mm (.040 in.) thick washer (2)
5*
Float valve
27
Connecting rod spring
6*
Gasket, carburetor body
28
Connecting link
7*
Float pin retainer
29
Adjustable bell crank
8
Float and pivot pin
30
Circlip
9
Air correction jet with emulsion tube
31
Adjusting segment
10
Carburetor body
32
Accelerator pump cover
11
Pilot air drilling
33
Screw
12
Auxiliary air drilling
34
Pilot jet
13
Bypass screw
35
Vacuum diaphram cover
14
Main jet cover plug
36
Oval head screw (3)
15*
Main jet cover plug seal
37
Vacuum diaphragm spring
16
Electromagnetic cutoff valve
38*
Vacuum diaphram
17
Main jet
39
Plastic cap
18
Volume control screw and O-ring
40
Choke heating element
19
Fast idle lever
41
Cover retaining ring
20
Throttle valve lever
42
Retaining ring spacer (3)
21
Throttle return spring
43
Small fillister head screw (3)
22
Accelerator pump injector
Keeping it real !
Thanks for the suggestions.
I've tried disconnecting the plug leads in turn and the idle drops off evenly with
each. Hence I don't have any lazy pots.
I forgot to mention I've also tried taking the air cleaner off and revving the motor, then blocking it with my had to try and such through any rubbish. It's hasn't made any appreciable difference.
It does sound like a classic case of a vacuum leak to me. I'll have a closer look tomorrow for vacuum leaks using WD40 and also test the idle stop solenoid. If I can't locate the problem I will take the carb off the following weekend and investigate.
Now I know where everything is located (pilot jet etc) it really helps.
Cheers,
Brett.
Brett Nicholson
Melbourne, Victoria
1974 VW Superbug L - Olive 😎
1971 Morris Mini Moke - Mopoke
1966 Austin Mini - Audrey
1965 Morris Mini Traveller - Trixie
2007 Land Rover Freelander 2
2009 Nissan Pathfinder
Well, I didn't find any vacuum leaks, but I ran out of time to check the solenoid. I'll take off the carb next weekend and clean it out anyway.
Is it worthwhile removing the manifold ends from the heads and renewing the gaskets there as well, just in case?
Thanks,
Brett.
Brett Nicholson
Melbourne, Victoria
1974 VW Superbug L - Olive 😎
1971 Morris Mini Moke - Mopoke
1966 Austin Mini - Audrey
1965 Morris Mini Traveller - Trixie
2007 Land Rover Freelander 2
2009 Nissan Pathfinder
If you can hear the solenoid clicking on and off with the ignition generally its working fine, but to double check just pull the wire off with the ignition turned on if it clicks its working
doing the manidfold gaskets witht he engine in the car is a PITA job, its not that often the leak there unless someone has reused the metal style crush ones
I had a similar issue with my 1600 TP, check that there is nothing blocking the idle jet...I had a piece of gasket blocking the jet hole. Once cleaned she was purring like a kitten...
Number 34 according to the diagram above - sorry "Pilot Jet"
Hi,
I haven't got around to looking at the Olive's problem yet. Hopefully early next week (I have the week off).
Cheers,
Brett.
Brett Nicholson
Melbourne, Victoria
1974 VW Superbug L - Olive 😎
1971 Morris Mini Moke - Mopoke
1966 Austin Mini - Audrey
1965 Morris Mini Traveller - Trixie
2007 Land Rover Freelander 2
2009 Nissan Pathfinder
Did you try cleaning the air bleed hole above the idle jet,this often blocks uo causing rich idle?I assume the throttle valve is closed fully with .004" clearance at the idle screw when the choke is off,then the mixture adjusted and the speed adjusted with the big air screw.
Brett.
The current engine I have is doing the same thing even though the heat risers are working. Mine is def icing under the carby which causes her to stall. Cleaning out the heat risers is a PITA.
Hi,
I managed to solve this problem on Saturday. (I think!) 👍
I removed the idle jet and blew it out. After replacing it, the engine was immediately running more smoothly. I backed off the idle screw on the choke arm so it was just off touching and adjusted the air bleed. I was rewarded with a steady idle at 700rpm. So far she hasn't stalled, but I've only driven her on a couple of short runs since and the choke was probably on the whole time.
I'd love to get the thermostat system working, but the necessary flaps in the fan shroud are missing, as usual. 🙁
Cheers,
Brett Nicholson
Melbourne, Victoria
1974 VW Superbug L - Olive 😎
1971 Morris Mini Moke - Mopoke
1966 Austin Mini - Audrey
1965 Morris Mini Traveller - Trixie
2007 Land Rover Freelander 2
2009 Nissan Pathfinder
