Won't idle and more

[burt]

At my wits end now engine won't start unless I pour a bit of petrol in to the carb
Then won't idle and cuts out I have rebuilt the carb the petrol pump is good
When reving the engine full it seems to suckling in air I think followed by a back fire then cuts out
Any ideas please

 

[Chico]

Sounds stupid but id do basics , rule things out ( not trying to state obvious or upset )
check firing order ( its easy to get that 1 o'clock vacuum , 5 o'clock 009 thing confused )
check leads
maybe disconnect the fuel pipe to your carb and run it into a bottle to make sure fuel getting through (safely obviously )
check manifold is secure tight , throttle cable working opening , fuel cut off on side of carb should hear the click when you attach / remove cable
( im presuming pict 34)
Chico

 

[Raggles]

When reving the engine full it seems to suckling in air I think followed by a back fire then cuts out

Check the timing ... could be too far advanced.

Is the fuel actually getting into the carb .... you don't say?

 

[burt]

Hi fuel is getting in to the carb but it just won't tick over
If I hold the revs in the middle then it's fine
It was running sweet as a nut 3 weeks ago I haven't done anything to it then it started playing up

 

[Raggles]

Hi fuel is getting in to the carb but it just won't tick over
If I hold the revs in the middle then it's fine
It was running sweet as a nut 3 weeks ago I haven't done anything to it then it started playing up

Have you checked for a vacuum leak ? .... base of the carb, manifold ... boots if a twin port?

 

[Tofufi]

Sounds like it could be an air leak.

On the carb facing you as you look into the engine bay, you'll see a plate the size of a 5p piece. Check it's still there...

You can see it to the left of this pic... http://images.thesamba.com/vw/gallery/pix/635751.jpg

 

[bac2ba6]

If its a stock carb ? Take the idle jet out (right hand side of carb by accelerator pump ) think it's an 8mm spanner and blow through it with air to make sure it's clear and screw back in .
If that's blocked it will cause idling problems

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[burt]

Right cleaned the jets out and there is a plate on the carb as mentioned in a reply still no good
Would a new carb fix it or how do I check the timing also the the timing has not been touched from when it was running fine
Ps it's a 1200 beetle engine

 

[Raggles]

I have rebuilt the carb

You don't say if the carb was a problem before the re-build and if so whether the problem was the same. On the rebuild what did you do? Was it a tear down and service with a service kit, or did you replace bushings etc. A worn throttle shaft bushing I believe can cause problems with the air fuel mixture (though others more experienced will know more detail on this).

Assuming that the carb is serviceable ... A bit of a pain but I think a slow and steady tune up might be the next step. Check everything ... even if it doesn't seem relevant. At least it will discount everything checked. A similar thing happened to me a couple of years ago (I had a completely restored & re-built original German Solex carb from Tim at Volkzbitz) and in the end I found the carbon contact in the top of the distributor cap had disintegrated .... although the symptoms screamed something to do with the fuel mixture at low revs.

If it was me I would go through the procedure step by step (do it again if you have already done this - just in case), including valve clearances for good measure, work through spark plugs, leads, coil, points, dizzy etc. Then reset the carb and do a test around the base of the carb and the inlet manifold for vacuum leaks.

 

[burt]

Right the engine had a small fire to start so I have replaced the coil the spark plug leads the dizzy the roatery arm the points all fuel lines air filter the fuel filter the fan belt the fuel Cut off solenoid thingy
Then it was running sweet started first turn of the key and drove nice and tucked over nice
Then all of a sudden from where I started to get problems
So I thought some muck might be blocking the carb some where
So I took it off and cleaned it down replacing certain parts with a carb repair kit
This has made no difference
Would it be easier if I brought a new carb
Thanks and sorry for being a pain
If I could drive it is would take it somewhere to be fixed

 

[Raggles]

I can only give you my thoughts.

If it was running fine and then something changed, it sounds like a failure or blockage of some sort. If the carb was running fine before ... then unless something has been put out of kilter during the rebuild, there should be no reason to replace the hardware. If you have access to (could borrow) a different carb then it would be worth swapping across to see if it makes a difference ... before going the whole hog and replacing. Buying new has its own raft of problems (hence I in the end went for a refurbished unit from Volkzbitz).

You say it runs sweet at mid revs ... so the carb is working.

I know on my motor, the boots to the manifold perished and i ended up with a vacuum leak via a crack, which weakened the mixture and stopped it idling. Same with the failure of the carbon contact in the top of the cap. Its also worth checking that all the spade connectors are good and tight on the coil ... I had one that was loose a while back and it stopped the motor idling though it drove fine at speed ... just cut out as soon as I came to a halt. Not obvious, but a very simple fix after 2 hours exploring everything else ... I replaced all the connectors and bingo!

 

[burt]

Thanks for all the help AGAIN good people of earlybay now starts and runs ok just need to fertal with the carb to make it run smothe as I've been messing with it
Thanks

 

[burt]

Right still one issue it now starts from cold really well but the warmer it gets it starts to struggle then after 5 mins it cuts out and won't start
Something simple I hope hope
Any ideas plz

 

[Raggles]

Right still one issue it now starts from cold really well but the warmer it gets it starts to struggle then after 5 mins it cuts out and won't start
Something simple I hope hope
Any ideas plz

I may be wrong but sounds like a carb adjustment issue. If it starts well from cold and then cuts out after 5 mins it could relate to the choke. Does it die completely, or does it run if you keep the revs up? If it runs with the revs up have you tried keeping it running for a while longer to see if it will idle when thoroughly warm?

If it dies completely when the choke has come off, then it would suggest that the mixture settings are wrong.
If it simply won't idle, it could be the mixture settings ... but if after longer running it will idle, it could well be the choke coming off too early.

These would be my first checks.

Initially I would try and reset the carb completely. Volksbitz has a good sheet on this here

http://www.volkzbitz.com/34pict-3---4-and-h30-31-adjustments.html

If you think it is the choke, you can adjust to stay on a little longer by loosening the 3 screws and turning the choke anti-clockwise a little, try 1/4 inch.

 

[burt]

Right still one issue it now starts from cold really well but the warmer it gets it starts to struggle then after 5 mins it cuts out and won't start
Something simple I hope hope
Any ideas plz

I may be wrong but sounds like a carb adjustment issue. If it starts well from cold and then cuts out after 5 mins it could relate to the choke. Does it die completely, or does it run if you keep the revs up? If it runs with the revs up have you tried keeping it running for a while longer to see if it will idle when thoroughly warm?

If it dies completely when the choke has come off, then it would suggest that the mixture settings are wrong.
If it simply won't idle, it could be the mixture settings ... but if after longer running it will idle, it could well be the choke coming off too early.

These would be my first checks.

Initially I would try and reset the carb completely. Volksbitz has a good sheet on this here

http://www.volkzbitz.com/34pict-3---4-and-h30-31-adjustments.html

If you think it is the choke, you can adjust to stay on a little longer by loosening the 3 screws and turning the choke anti-clockwise a little, try 1/4 inch.

Thanks again got I right in think

One more question
Does the fuel pump line out look dangerous because if the belt snaps I looks like it will hit it
Is this the correct pump

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[Raggles]

I don't know if it is wrong, but it is different to mine. Seems odd that the fuel line is located near the fan belt.

 

[burt]

I don't know if it is wrong, but it is different to mine. Seems odd that the fuel line is located near the fan belt.

That's what I thought

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[Raggles]

your set up appears to be using an alternator.

This would I think be the correct pump to go with the alternator.

https://www.vwheritage.com/113127025g-fuel-pump-for-100mm-alternator-rod-repro

Though i recall that the rod lengths vary depending upon the set up ... so needs checking.

 

[Bluesnailman]

If its a stock carb ? Take the idle jet out (right hand side of carb by accelerator pump ) think it's an 8mm spanner and blow through it with air to make sure it's clear and screw back in .
If that's blocked it will cause idling problems

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there is a second jet near this one, might be worth taking this out and clearing it too. less likely would be the passage on the rhs (outside of the carb) from the squirter diaphragm (it deals with sudden depression of throttle). I had two attempts at dismantling and cleaning mine before the idle circuit worked properly - (and the second kit I got had much better gaskets too). best of luck, painful exercise this...

 

[burt]

If its a stock carb ? Take the idle jet out (right hand side of carb by accelerator pump ) think it's an 8mm spanner and blow through it with air to make sure it's clear and screw back in .
If that's blocked it will cause idling problems

Sent from my SM-J500FN using Tapatalk

there is a second jet near this one, might be worth taking this out and clearing it too. less likely would be the passage on the rhs (outside of the carb) from the squirter diaphragm (it deals with sudden depression of throttle). I had two attempts at dismantling and cleaning mine before the idle circuit worked properly - (and the second kit I got had much better gaskets too). best of luck, painful exercise this...

Hopefully I've got it fixed may have set the choke wrong when rebuilding the carb going to take it out for a test Ron on Saturday so fingers crossed thanks

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