Carb Issues - Beetle 31 PICT-3

[No More Landy]

I got my motor running, but soon after the choke came off it started running poorly despite the timing being correct and I tried adjusting the fuel and idle screws and it was not helping much.

So I decided since I had a rebuild kit from an old beach buggy I owned years ago, I would replace the gaskets and give the carb a clean out.

I found a lot of gunk inside but nothing seemed blocked to the eye. I also found the spindle nut holding the throttle arm was fairly loose so I nipped that slightly and bent up the tab washer again.

I then installed a fuel filter below the tank as there was none in the system.

Once fitted, the carb has a terrible flat spot, especially on corners and the engine often dies when I come to a stop.

I adjusted the Fuel and Idle screws as per most of the good You-Tube videos and she idles OK when not driving but she dies all the time and struggles to pull away unless you give it a few revs first. Once going in a straight line she pulls well, it is just the idle and pull aways.

The car was running fine before I opened the engine to change pushrod seals.

Plugs set at 0,6, points at 0,4 and inlet and exhaust tappet clearance at 0,1.

Can it be something to do with tightening the spindle nut ? There is only very slight play, hardly noticeable on the spindle bush on the lever side.

[Tony Z]

have you checked for vacuum leaks?

[fig]

As Tony said, your symptoms are most likely caused by a vacuum leak, either where the manifolds connect to the heads, or at the manifold joints if you have a twin-port engine with the 3-piece manifold. This is the most likely cause since you've recently had the manifolds off.

Also check that you are using the correct carb port for the vacuum advance tube. The 31PICT carbs have as many as 3 different vacuum ports, most of which should be plugged.

A bad condensor can also cause these symptoms.

Is your engine single or twin port? What distributor are you using?

[No More Landy]

Have not done a leak test - how do I do this ? Edit: Just saw comprehensive instructions from Tony Z at top of this forum list

Another possibility is - my manifold heat riser pipe was completely blocked so I drilled a hole in the corners with a long series drill bit right through to the opposite side but I could not clean out the remaining carbon in the horizontal part of the tube as it was blocked solid. So I basically only have a 6 mm diameter channel through the horizontal part of the heat riser pipe but the vertical parts are clear.

I also had my welder at work fit a new elbow and short piece of pipe to the heat riser which was rotten, but he did this while the riser was bolted to my new exhaust so it fitted well and there was no tension when I removed it again.
However, when I came to reinstall the manifold and tie up the heat risers to the exhaust, there was a now height difference on the one riser and I had to pull it down by about 6 mm or so, so maybe that is pulling somewhere and causing a bypass of air. The manifold rubber boots are new and fitting fine and the twin port manifold has new gaskets.

The distributer is VW 113 905 205 AJ

[fig]

Blocked heat risers can cause flat spots, but usually only when cold. Their purpose is to prevent manifold icing in cool, damp weather. You won't have a flat spot when warm if the heat risers are the problem.

Your distributor is the correct stock SVDA, so that shouldn't be the problem.

Back to vacuum leaks ...

[No More Landy]

Blocked heat risers can cause flat spots, but usually only when cold. Their purpose is to prevent manifold icing in cool, damp weather. You won't have a flat spot when warm if the heat risers are the problem.

Your distributor is the correct stock SVDA, so that shouldn't be the problem.

Back to vacuum leaks ...

I thought more along the heat riser misalignment was pulling the intake manifold parts and causing an air leak.

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[No More Landy]

Ready to test tomorrow. Been working most nights until 22h00 for the last two weeks. Getting pretty knackered but learning plenty especially from this forum. Thanks guys for sharing all your knowledge. Us newbies really appretiate it.

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[slak]

i Think someone changed your jets at some stage
the correct jets are 130 main 110z air and 52.5 idle jet
those that U have seems really big

[No More Landy]

i Think someone changed your jets at some stage
the correct jets are 130 main 110z air and 52.5 idle jet
those that U have seems really big

It was listed as 1300 but the guy who sold it to me said it was converted by his b.i.l to a 1600.
Jurgen at grand slam said maybe the barrels and pistons were converted but the carb and manifold are still 1300 but he said some guys increase jet sizes ?

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[No More Landy]

Should this extra pipe on the vacume be connected also to my Carb ?

There is an extra tube on the carb that is blanked off.

[retrovan]

Have a look at your fuel level in you float chamber, this may also flood the engine on bends and on braking.

You can adjust this by adding washers or removing washers.

Herman

[No More Landy]

It was not overflowing but seemed fairly high. Is there a dimension one can measure from the top edge of the bowl ?

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[retrovan]

There is a difference of opinion,

Some say 12 mm others say 14mm

I have set mine at 14 mm

Herman

[No More Landy]

Thanks Herman. Will measure tomorrow and report back. Do I add Cu washers or do I machine a custom washer by adding reading minus 14 mm

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[No More Landy]

Is that measurement with the float removed?

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