Accelerator pump setting question: Solex 31 PICT-3

I've seen the nozzle in all sorts of different positions! On my present unmolested carb (17k genuine miles ) it's just above the choke spindle, on my old carb it was pointing to the right of it.

There is a way of checking the stroke of the accelerator pump by how much fuel it squirts in so many pumps (haven't got the spec with me :-( ). You'll need a small measuring tube to do this.

My hesitation from low revs was cured by rebuilding the dizzy and putting on a new vacuum advance. Having the ignition timing too far advanced can make it hesitate at low revs. I would also check the carb throttle spindle for leaks, if you see fuel drip from the bolt ends then you'll get air leaks and won't be able to tune the carb properly.

--Steve

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I'm currently preparing my -73 Beetle for the summer. I cleaned the carburettor and put in a rebuild kit. My problem has been intermittent hesitation when accelerating from low revs. Sometimes it goes, sometimes not. The carburettor is a Solex 31 PICT-3 (1300 DP engine with Bosch SVDA). To kill the hesitation I'm now rebuilding carb, cleaning and lubricating the distributor, renewing all vacuum hoses, doing a complete tune up to valves, carb and ignition.

Two questions:

• what is the correct orientation for the accelerator pump jet nozzle that points down the carb throat?

• what is the correct way to set the accelerator pump stroke length? Is it trial-error, volume of squirt or lenght of squirt in throttle flap opening degrees? What is the correct setting?

I've read different info on this. Some say that it should squirt = straight into the manifold (to the throttle opening). Some say that it should=20 hit the throttle flap to help the fuel vaporize. I would be interested knowing the right direction or does it really matter if it works both ways.

So you rig up a hose to the nozzle and squirt away like 10 times and = then=20 measure what you have in the cup?

I found the spec and it says: Einsprizmenge 1,45 +- 0,15 cm3/Hub. ... I guess correctly from the German terms. That would be 1,45 = millilitres per squirt wouldn't it and 14,5 ml for 10 squirts. Does that sound = right?

Ok. So this intermittent hesitation could be eg. because of a sticking mech advance. If that of some reason won't return to normal and when accelerating there would be too much advance? And then other=20 time it would work quite ok.

I have a 043 905 205K -dizzy in the car, which according to ETKA is from a Rabbit 1300 46 hp engine (AF-block). Correct one for the 31 = PICT-3=20 carb would be 113 905 205AL. That AF-engine is listed with 34 PICT-4 = carb.

My engine has apparently been rebuild in the VW factory. It has that = kind of stamps in the case and carburettor id plate. They could have replaced = the dizzy there also. I wonder if those two distributors are too much = different.=20 Would be nice to find the specs for all the carbs and dizzies somewhere = to=20 compare.

I haven't seen it leaking gas at all.

Depends on engine. Usually the jet should run very close to the throat wall, so that it will shoot through the throttle valve gap as it starts to open. On some engines I have received better results if I adjust teh spray so that it first hits some obstacle in the carb throat and "splatters" on impact, then gets sucked in. Gives a delay effect. But this is just a band aid. it SHOULD point straight down, and have a clear path to flow right through the carb without hitting anything on the way through. Not even the throttle plate.

In theory, there's a recommended volume amount which is counted by measuring 10 full strokes into a beaker, dividing the result by 10.

In real life it's just trial and error. Motocross and mistake.

Jan

Oh. Turbo mode. I have to get a sticker to the back lid.

And if I set the lenght of squirt too high? How will that affect or=20 is it only seen in the mileage?

COnsumes more fuel, washes oil off cylinder walls, causing accelerated wear. Poor acceleration due to over-rich mixture not burning properly. Blows a puff of black smoke out of the tailpipe.

Jan