Just won't idle - losing the plot - what else can I try?!

[Termite]

Yes, I'm beginning to weigh that up as an option . Buying a second hand one though will come with its own set of unknowns .

VW Heritage don't list a price for a turnkey engine, presumably as you can bolt so many different extras on to it.

 

[DubBGood2Me]

If you have the same issues with a different carb then maybe the carb isn't the issue? Possible fuel pump problem? Might not help but thought I'd add my two pence worth. Hope it gets sorted

 

[Termite]

I'm beginning to wonder if it's crap fuel from France :lol:

I think the fuel pump is fine as the carb bowl has been empty each time I've put the carb on, but when removed it's full enough to have the float high up to shut the needle valve off.

Could crap fuel make it idle rubbish but be ok when accelerating, revving? There's around 1/4-1/2 a tank in there at the moment, so maybe I'll try a couple of jerry cans on top of that at the weekend.

 

[Dickie524]

Lots of E10 ethanol fuel in France.

 

[dustrat]

You seem to be having your fair share of problems with that carb. Go back to basics.First remove idle jets. These are on the right hand side of carb which at 4 to 5 oclock to choke. 1 is straight forward screw out and the other you screw the blanking plug out and use a thin screwdriver to get at jet which is recessed inside. Make sure these are clean and then use airline to blow out any blockage that could be there.Have you altered the screw on throttle arm? To set the fast idle adjuster make sure you pull the choke off and then scew adjusting screw in so it is just touching cam and then screw it in 1/4 turn.Once this set do NOT alter. as this sets the throttle buterfly. Next turn the volume control screw( the smaller one ) in and turn it out 2 1/2 turns and the larger screw,bypass out about 2 turns.Start engine and ajust bypass screw to get it to tickover at about 850 rpm. go back to volume control screw and ajust for fastest idle,ie 1/2 a turn in or out and then turn in slowly until revs drop and then use bypass screw to get revs back to about 850rpm. I've copied this from a article from Rob and Daves Aircooled Volkswagen Pages and have used it many times to set up 34 pict 3 carbs and I hope it works for you.
Robert
Just as after thought make sure your dizzy vacumm pipes are OK and that any vacumm intakes on carb that are not used are blanked off.

 

[Termite]

I've taken those jets out twice now and are definitely clean. One thing you've mentioned that I haven't done is set the throttle screw against WITH the choke removed. I've done it with the choke in place and held the butterfly open while I set the screw. I guess there's an outside chance that's caused a problem?

The three holes at the base of the carb, should any of those be exposed when the throttle screw is set, or does the carb just rely on fuel running down the side of that butterfly?

I have two more Solex 34 PICT 3 carbs in a box. One has been a donar at somepoint as there's bits missing from it. The other is one I boxed that I was going to send away for refurb a few years back as it was leaking fuel and letting air in round the throttle spindle. I have since got some brass bushes, so I might have a go at cleaning that one out at the weekend, fitting the rubuild bits to it and trying that on the van. At least I know that carb was once on the van itself and I've driven it while it was on there.

 

[Bluesnailman]

I'm in York, so can't lend you mine.....

if you're absolutely sure that you've cleaned the bypass circuits like above, blow air through the chambers etc then you might want to try a new carb before you splash on an engine. seems a bit too dramatic to me.

changing the fuel over might not be a bad idea. or adding some 'super' to the existing. Ethanol in petrol attracts water, but the water would sit on the top and your fuel feed is from bottom of tank - so might not be the issue

 

[dustrat]

When you set the fast idle ajuster properley as explained this sets the throttle butterfly at the required .004inch to allow fuel for tickover.
Robert

 

[Termite]

I'm in York, so can't lend you mine.....

if you're absolutely sure that you've cleaned the bypass circuits like above, blow air through the chambers etc then you might want to try a new carb before you splash on an engine. seems a bit too dramatic to me.

changing the fuel over might not be a bad idea. or adding some 'super' to the existing. Ethanol in petrol attracts water, but the water would sit on the top and your fuel feed is from bottom of tank - so might not be the issue

When I've cleaned it I've done the following...

* Took the top off the carb
* Emptied the fuel out into a jam jar
* Took the idle jet out and the little screw next to it, then pulled the tiny jet out.
* Blew air thorugh these
* Put them in a cup of carb cleaner
* Blew air thorugh the circuit (big puff of fuel vapour out of holes in the carb)
* Repeat above for any other jet/bolt etc.. that can be removed from the carb
* Covered carb in carb cleaner
* Cleaned with toothbrush
* Cleaned stubborn bits with brass brush
* Rinsed with carb cleaner
* Blew all holes again with compressed air to get the carb cleaner out
* Reassembled carb with any new washers, valves, o-rings etc.. that were in the kit
* Lifted carb and got as close as I could to it while I turned the throttle screw to the cam. Backed it off so I could see the white of a piece of paper between the cam and the screw.
* Slowly turned the screw until it just touched.
* Put carb down and turned it 1/4 of a turn to set the 0.004 bit
* Refitted gaskets and reattached to the manifold in the van.

It took 3.5 hours to do the above on Sunday.

I'm going to strip and put together a 3rd carb tonight. If that fails, then I am an idiot and doing something wrong or extremely unlucky and have 3 knackered carbs :mrgreen:

Everything I read about new carbs are that they aren't very good and to go back to a Solex.

In my other thread where I mentioned a knocking noise, that has quitened right down with the oil change (which did have some little bits of brass coloured metal in it) and the cylinder pressures were 115-105-70-102psi when I did a test on Saturday. Before I went away they were all around 130psi. On Sunday I tested pressure again on cylinder 3 with a drop of oil in it and it read 85psi. I turned it over two more times and it still read 85psi, so maybe on Saturday I didn't have the compression tester screwedin tight enough (I wouldn't have thought the oil would "seal" the piston rings for that many engine turn overs). Either way it is a lot lower than the others.

Only other thing I've not tried yet is a different distibutor. I've sucked on the vaccuum pipe and the points move around as expected and the engine does advance when the timing light is connected, so I don't have a reason to suspect that is an issue. At idle it's not doing anything special anyway is it?

Thanks for the comments so far.

 

[Termite]

So 3rd time lucky (sort of).

Stripped and rebuilt the 3rd carb (original one on the van) and rebushed it with brass bushes. Set the big screw at 2.5 turns and the little one at 2. It ran on choke but yet again cut out when it hit the last but one notch on the choke cam. Before I stripped it, I counted the number of turns it was set at and the big screw was 1 turn, the little at 3.5.

I changed the settings to that and it idled for a bit longer before chugging to a halt. I backed the big screw out a turn and it idled very lumpily, but idled long enough for me to move to the back of the van and get the screwdrivers out. I now have it idling at 2.5 turns on the big screw and 3.75 on the little screw.

Video here - https://youtu.be/XTYugRwPklM" onclick="window.open(this.href);return false;

I think it still needs fine tuning/playing about with as well as tightening up the fan belt that looks like it's flapping around a bit, but it was 10:30pm last night when I got it running and didn't want to pee the neighbours off too much! But it's progress and finally gives me an idea that nothing else is stopping it running. Next step would be to try one of the other carbs I had issues with on similar settings to see if they do run.

First time I've smiled in about a week! :mrgreen:

 

[Bluesnailman]

good news indeed!! if you have an aftermarket carb or screws I wouldn't worry too much about the number of turns in our out. I've no idea what mine are at - so suggest you fine tune now that you're running and idling. Industrial estates at the weekend make a good place to do your fine tuning.

 

[Dickie524]

Did I read somewhere though that you have found little brassy bits in the oil?

 

[Termite]

Yes, you did read that.

Tomorrow after football (so late afternoon) I am going to start it up and go for a drive 20 miles or so and then do another oil change to see if there's still anything in the next change.

I think someone mentioned distributor gear is brass, but what else could it be? Valve seats/guides? Bearings?

 

[Dickie524]

We-ell - if the distributor gear is brass, and say it has lost a tooth r broken several teeth - there is a potential that the timing would be all over?. I might be tempted to pop the dizzy cap off and see if the rotor arm can be rotated by hand - will tell you if there is 'play' at the other end...

AS for why that would have led to low compression elsewhere I'd be struggling - unless somehow a fractured piece of gear could have got trapped by one of the piston skirts and scored the inside of one of the bores...?

Hmm.

Perhaps someone more familiar with VW engines than me will know whether it's possible to see the inside of the dizzy gear by looking through the sump plug?

 

[Termite]

Ok, so still idling lumpy but managed to get it out for a spin. Cut out a few times then when I was at some lights I revved the nuts off it a few times and it stopped cutting out after that, but still runs lumpy.

Did some driving about and dropped the oil (it's not done 50 miles since the last oil change). No bigger bits of brass in it, but there certainly is small metal/brass bits in the oil...





I am guessing this is not a good sign and probably time to give up trying to get this one to run and pull the engine...

 

[Dickie524]

Don't look great do it? :-(

Sorry to hear that dude, someone must know what other brass bits there are in there...

 

[Termite]

No, looks like I'm running on glitter.

 

[Termite]

Ok, knowing the above, would you continue to drive it for another say 400-500 miles?

 

[Bod]

I think that your big end bearings have gone. Happened to my old astra. No harm in driving it if you are going to get a new engine with all new ancillaries.

 

[chug]

Exactly the same as the brass I found in mine, I put mine down to the brass gear (on the crankshaft) failing for a previous owner and not being cleaned up properly after.

How long have you had the van/ engine if second hand? always good to know what may have caused the fault.

Other brass components (I think) are the little end bushings in the conrods, to find that amount of brass in the oil though, the fit between the gudgeon pin and the rod would be really sloppy and give you a rattle/ knock.

It does look like the brass has got into the main bearings and wiped them out.

If you do decide to rebuild it you may be lucky and find the cam and crank re-useable, definitely fit a new oil cooler as the brass particles will be in there aswell.

I removed the oil galley plugs on mine and tapped the holes for fitment of tapered plugs, this allowed me to fully clean the galleys with galley brushes.

Have a read of this, it shows the brass gear http://www.thesamba.com/vw/forum/viewtopic.php?t=415546" onclick="window.open(this.href);return false;