Misfiring weber conversion

[black betty]

have just swapped the old single choke vw carby for a twin choke weber DGR 32

engine is a 1991 1800 from mk 2 gti

before the swap the car ran well

now it misfires slightly on tickover

also it appears to misfire fairly badly under acceleration (partial or full throttle)

it also "runs on" for a few seconds when you switch the ignition off after a journey

when i did the swap i used a new carb to manifold mounting gasket/ plate

there does not appear to be an air leak- i have sprayed carby cleaner around the mounting when the car is running to see if any change in revs (from an air leak)

as such i think that the ignition timing is out and wonder if anyone can please answer the following for me:-

1.is the ignition too far advanced or retarded?
2. which way would i have to twist the distributor to adjust this (i.e. clockwise or anti-clockwise?)

any assistance greatfully appreciated

bb

[Golfwise]

misfire

If it was running ok before the you changed the carby don't confuse matters by changing the timing or anything else.Concentrate on the carby .
Anticlockwise for advance, opposite to retard .

[black betty]

thanks golfwise

sorry should have said- i paid someone to 'service' it after i had put carby on

they 'played' with the ignition timing to no avail

think i want to try and sort it myself and not spend more money on it

as such do you think they might have advanced the timing??

also when you say concentrate on the carby- could that make it misfire and run on etc i.e. jet sizes

sorry i do not have a lot of experience with carbs

[syncro]

What is the distributor out of?
What was the original carby out of?

[gotrice]

Carbies are dirty untuneable things. Bite the bullet and go for injection and you wont regret it. I did and am soooo happy with it.

Or take it to a VW place (There are two in Canberra that are good) or a carby place and have them check it out. But unless the carb has been set up for your application then it will use too much juice and run like a dog. If your lucky it will go a lot louder but not any faster and you also heat up your exhaust by putting too much fuel through the engine so the unburnt stuff gets burnt in the exhaust.

[Anonymous]

syncro-

the carb is twin choke from a gemini (similar engine cc's i believe)

i think the innards (chokes?) are 26 and 28

i think the distributor is from a mk 2 gti in that it has the vacuum advance thingmo on the side of it (which i have connected to the carburettor by a vacuum line)

gotrice- the car is really just a toy and i wanted to get a bit more fueling than the single choke without spending too much $$$ so unfortunately fuel injection is a no goer for this project- but in an ideal world.....

[syncro]

Distributors from digifant engines do not have mechanical advance. May be worth looking into????

[Anonymous]

Mate ive had the same problems before.
Im not expert but for me it was the set points. I replaced them and they were fine.
I dont nkow about u guys but i reckon carbys sound mad, esp webers. Got to love them for that

[Anonymous]

okay heres an update- i gradually adjusted the ignition timing by turning the dissy clockwise and retarding it

each time i took it for a drive

i have got to the stage now where:-

-misfiring at idle is gone
-misfiring under load has pretty much gone
-generally runs quite well

however it is still not the ball of fire i might hope it would be!

at least i know it seems to/ will run reasonably well so i am going to book it in for some rejetting at a dyno on monday or tuesday

a couple more questions:-

1. should the carby hiss continually until you really put your foot down?
(i.e. when only the first butterfly is open)
2. how much should i expect to pay for a quick set up and some jetting on a dyno??

thank to all of you for your help so far

bb

[Golf Loon]

I`d be taking the carby off and to pieces blow it through with air, then it should work better. Just had the Mk2 carby on and off 3 times. its right now.

At least you know the points and timing are ok.

Did you make an adaptor plate to fit that carby? or modify the inlet manifold?

Do you still want these wheels?

[black betty]

hi matt

had nt heard of blowing air through the carby before- might give that a try

as for the inlet manifold i think it is genuine VAG off a solex carbed mk 2 or a passat or something- it has 4 upright bolts on it

bought a new gasket thingmo for a 32 DGR and it bolted staight on and connected the water pipes up to the bottom of the manifold- pretty easy really

worst thing was adapting the air filter as it kept hitting the bulkhead

anyway yeah i still want the wheels- been really busy of late work wise but thats calmed down now so will be in touch soon

cheers

bb

[Golf Loon]

If you are feeling lazy and dont want to take the carby apart goto the servo and just use the air to blow down every opening you can see with the filter removed and the engine off.

Used to unblock the jets on my webber powered polo back in the day. The idle one always blocked for some reason.

That manifold was a good find