flat spot

[atlime]

Anyone have any idea on how to cure a flat spot on a 71 westy with single carb?

It runs fine when started from cold but after 2 mins when its warmed up it gets a flat spot where you either have to be very gentle with the throttle of keep it reving high

The guy I got it from said he had checked the timing and few other things but not sure what....


I had a nosey about in the engine bay today and have noticed a few things.

one thing is that there seems to be a pipe missing from the air filter, Is this the flapper thing?



Secoond thing is there are 2 holes on the carb that are plugged up. Is that correct?



And finaly...does anyone know what this is on the right side of the enigine bay above the batterie..again there seems to be a pipe missing from it!




And here is a pic of the entire engine bay



thanks for any advise

 

[TheBusDriver]

The flat spot is most likely caused by your distributor. A009 and a 34 carb are a bad match. An original style vacuum advance distributor will most likely make it run better.

The thing above your battery is a charcoal canister.Its part of the emission system. It should connect to your air cleaner.
It should not be part of your problem. Most people I know have removed them now that they don't have to do emissions testing anymore.

 

[Araon]

first pic your missing 2 hoses, corrugated warm air and not sure on this one but suspect its the evaporative fuel input

the canister is an evaporative fuel charcoal filter, input from fuel vent, input from fanhousing and output to airfilter (above)

the carb right two vac lines, some use the upper for the DVDA dizzy as the retard, but both these are used with the throttle positioner altitude adjuster used to set up the delay in throttle shut down

as your running a 009 dizzy you should have another vac port blocked on the left side....

 

[robins]

is there somthing missing of the manifold :?:

 

[atlime]

I take it the 009 are not the right dizzy then?

Why do they get used if they cause sooo much problems...I have been told by several people its the 009 causing the problem.

Do they always cause problems or is it just when its used with certain carbs?

What dizzy should I fit with my carbs then ? :? Can I get from JK or heritage?

 

[Araon]

The 009 is a contraversial beast but the main use for them is fixed rpm engines or racing purposes......

that said if you go the electronic ignition route it will be fine as long as mechanically its sound

keen eyes Robins, looks like a heat pipes missing

 

[noddy]

That doesn't sound like your distributor unless the timing off. It sounds more like a blocked accelerator jet in the carb.

009 should transition ok from tick over to running especial when not under load. (I agree vac dissy is a better option smoother advance and no low rev flat spot).
If you having to open the throttle slowly to stop it stalling its because the mixture is not getting enriched by the accelerator jet, or your pulling loads of air from somewhere other than through the carb.

 

[atlime]

If I keep the revs high I can go through the gears no problem...just dont like doing that to the engine :shock:

So its eitehr really low revs and it eventualy gets moving or high revs.

I have also found that tapping the throttle until it gets past the flat spot works

 

[Araon]

You got a pic of the carb from the left viewing over the dizzy also is there any movement in the throttle splindle....

 

[noddy]

Definatly sounds like the accelerator jet has a blockage.

take the rubber air tube of the top of the carb. look down the throat of the carb you should see a small tube with a downward pointing jet at the back of the carb (thats back of vehicle ie closest to you).
Pump the throttle linkage by hand and you should get a clean squirt of fuel from the accelerator jet, if not you will need to strip the carb and flush it with carb cleaner.
A hand held mirror makes it easier to see down the carb.

 

[atlime]

Aaron,

On the left side of the carb just above the mixture screws there is another piece of pipe blanked off (like the 2 in the pic) PLUS another on the left side blanked off that is on the inlet manifold?

No pics yet as batterie is flat!

Should that be connected up?


Throttle spindle? take it thats what the throttle cable goes round...doesnt seem to be any slack in it no


Noddy,

Im searching for a mirror now to check on the jet

 

[Araon]

That needs to be blocked, the spindle is the long bar running across the base of the carb and has the two cadmium coted levers attached, throttle valve lever and fast idle, check for excess movement/wear....

If the bushes are worn then air can get in here on operating the accelerator....

 

[atlime]

Aaron,

Just check with a mirror and can see the jet pointing down and it does squirt fuel ok..

seem to squirt it towards the back of the carb (back of the van direction)

is that right?

Here is a pic of the left side of the carb

 

[noddy]

Yep thats ok so not the cause of you problem.

Next thing is are the centrifugal weights in the distributor moving ok and are your points gaped ok?
If the weights are sticking you should notice a sudden jump it the advance when the engine get to a certain rpm.
Do you have a spare dissy you can fit to test if it is the dissy thats the problem?
Also that drilled hole in the back of the carb shown in the last picture is air getting drawn in through it when the engine is running, easy test just put you finger over it, if it is drawing air block it off.

Also looking at your pictures it looks like the screw that positions the throttle on the stepped cam is too far in.
The end should be about the thickness of a piece of paper off the bottom of the stepped choke cam when the choke is open.
If you get this set and your tick over goes way down use the tick over air screw on the side to bring the tick over back up to around 850 rpm, its the larger of the two screws near the fuel cut off valve. The small screw is the tick over mixture screw base setting for this is 2.5 to 2.75 turns out from fully home (dont screw this hard in if resetting, just a light touch then back out. If you jamb it home its wrecks the end of the screw and makes it hard to set the mix)

 

[aogrady]

Hi!

You can run a 009 on a stock 34 PICT 3 - here is a link for you to try!

http://www.airsupplyvw.co.uk/flubberdubbers/solexwith009.html" onclick="window.open(this.href);return false;

Stuff on Google........

http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=T1V&q=Solex+34PICT+3+and+009&btnG=Search" onclick="window.open(this.href);return false;

Never tried it myself, as i have a vac dizzy now, but worth a try.

BTW I'd move your fuel filter away from the sparks - and re-route it under neath near the fuel tank, less potential problems and leaks, and while your at it replace the fuel line from tank to pump and carb, not a lot of money, and peice of mind, the old pipes can leak and split and you may not notice the cracking till it's too late......

Set up yor carb - all the info here:

http://www.vw-resource.com/34pict3.html" onclick="window.open(this.href);return false;

Cheers!

Alistair

 

[robins]

what is all that silicone hiding on the front of the carb :?:

 

[easy]

what is all that silicone hiding on the front of the carb :?:

Im guessing its missing its blanking plate, silicone works better than a cork

 

[atlime]

When you look at the silicone it look like its just slapped on the side of the carb ..Cant see anything obviouse behind it !


Not sure I want to pull it off either! lol


Anyone know what the correct setting for the point will be?

 

[steve92]

When you look at the silicone it look like its just slapped on the side of the carb ..Cant see anything obviouse behind it !


Not sure I want to pull it off either! lol


Anyone know what the correct setting for the point will be?

0.016 inch/ 0.4mm

 

[atlime]

Just went to do the points and there aint none :shock:

Must be electronic!