Backfiring and stalling.

[Dave307]

He he, from the symptoms I am going to stick my neck out and go for a blocked / obstructed primary main jet.

£5 to the charity of the OP's choice

Ok then so if that's what you think what do I do to sort it. Bear in mind you talking to a novice.

[ghost123uk]

He he, from the symptoms I am going to stick my neck out and go for a blocked / obstructed primary main jet

Ok then so if that's what you think what do I do to sort it. Bear in mind you talking to a novice.

If I am correct (and it is now well into Friday evening ) then see my post =

Assuming this is a flat 4 petrol engine with a carb (ie not fuel injected 2.1) then this sounds like the classic symptoms of a blocked primary main jet in the carb. (the main jet underneath the smaller of the 2 choke chambers)

You would need to split the carb to check this = dead easy, the air filter, a fuel pipe, a wire or 2, a throttle cable, the water pipes for the auto choke, 4 cross head screws and the top of the carb comes off. Then check that main jet and the other jets, DO NOT poke wire through them, blow or use a bristle from a yard brush (or similar softish poker).

The only problem you are likely to come across is the gasket often gets damaged on splitting the carb so you will very likely need to source one first (or be off the road until you get one), btw, DO NOT use ANY gasket goo on the carb !

Don't forget to bleed the cooling system after having had the water pipes off the auto choke unit.

p.s. = source = had this on our T25 last year and our Scirocco (same carb) last week!
Where these bits of black gunge come from is a mystery as both vehicles had good fuel filters.

E D I T = gasket from = http://www.ovalracingforums.co.uk/viewt ... f=6&t=7992" onclick="window.open(this.href);return false;
We stock the top gasket for the pieburg = http://www.atspeedracing.co.uk" onclick="window.open(this.href);return false; - tel: 01268 773377
And probably Brickwerks too of course (tho they may only do the full service kit)

Hope that helps, but if you are not confident at doing this, I bet we have someone near you that can check this , and the other suggestions above.

Either way it does not sound like an expensive / big problem

[Dave307]

Right I'm on it tomorrow morning. Will have to source a gasket first thing.
Thanks.

[ghost123uk]

Right I'm on it tomorrow morning. Will have to source a gasket first thing.
Thanks.

I hope I am right now The other suggestions are perfectly valid (I bet I am right though...)

[ermie571]

Oh, and you have to promise it that you will never run out of petrol again. Ever.

Em
xx

[ghost123uk]

You know, this running out of petrol and therefore sucking up crap from the tank is an urban myth.

The pick up pipe in the tank is set at the lowest level possible. This means that it will always be fed from whatever is at the bottom of the tank, be it crud, water or whatever, regardless of how much fuel is above it. So, in theory, no "extra" crud should be fed to the in line filter or the carb than when the tank is full or when it is nearly empty.





However, experience seems to outweigh the facts

[HarryMann]

But pickups usually in a well, designed to let crap settle out of wayof pickup itself, canny design, supposedly...

So, have you tried the patented ' suck the crap out of the fixed jet' method, uisng rev-up and hand over choke inlet, as described by yours truly on here many times (but too fagged out to wite it all up again) ?

If not, will try to find a link in the Tech Archive for you, if its crap blocking then it usually works

[ghost123uk]

No need to write it up again as your words above should be sufficient And a good point, it's always worth a try before you go ragging a carb to bits

[Dave307]

Right I'm Out to try all the above. The gasket I need to re house the carb appears to be a bugger to source. So all other methods to be tried first.

[ghost123uk]

Actually when trying the rev, block top of carb to suck muck through the jet trick, I tend to use a book (Heynes ) over the carb top as the suction against your hand can be a bit wierd. Don't forget the engine will be a bit flooded with fuel immediately after you do the suction thing.

p.s. = I am told that a Diesel engine can suck your hand inside out (not that there is any point in choking a Diesel engines air feed in this way)

[Dave307]

Ok new inline filter fitted last one was black and full of crap. Nasty. Did the choke in let block and rev thingy. New fuel filter is still all clean after running.

Anyway I'm now off to test it. So fingers crossed.

Oh by the way I could only get 2 fingers in to block the choke. The airfilter pin were in the way to get whole hand in. It still choked the engine tho and I did it a few times.

Any way as I said keep your fingers crossed.

[ghost123uk]

Oh by the way I could only get 2 fingers in to block the choke. The airfilter pin were in the way to get whole hand in. It still choked the engine tho and I did it a few times.

No need for fingers on the choke flap, in fact that is less likely to achieve the desired amount or suction (vacuum) in the carb body.

Standard (well my) procedure here is to rev the engine, quickly shove a book on top of the entire carb, then open the throttle again (wide open) it won't rev up properly as no air can then get in, but it sometimes sucks the crud out of the jets. If you are doing it right the engine will strangle itself to a halt (no air). You then usually have to crank it a bit to re-start due to the excess fuel in there from this very "forced" starving of air.

Hope that makes sense, if not post back for more detail

[Dave307]

Hi all

Ok so just been on a mission to the beach in the van having done all test and suggestions that were noted on here.

So far so good. No stalling no backfiring oh except once just after we set of. Then good as gold.

So I have my fingers crossed that it's sorted.

Thanks everyone. Your all quality. Think I need to learn more about these vans so more reading a dumb ass questions from me.

Thanks again.

[ghost123uk]

Ok so just been on a mission to the beach

I wish we lived near a beach

Hope all is well

If not, ask away

Hic...

[HarryMann]

That's right ghostman, spot on...

Can be done in different ways to suck against different jets, deopendent upon the way the throttle is opened rapidly and exactly when the choke is choked - suction can be enormous, correct, a flat is usually OK though, best gloved..

If the throttle is still opening (being moved steadily, even rapidly) as choke is sharply blocked can even put dirt/muck cleaning suction on the emulsion tube(s) and accelartor pump jets

Yes, suibsequent richness can stall engine unless very sharp with removing blockage and re-opening butterfly.