Had a great day up at Stockton on easter sunday but had a few little hicups along the way!!!

The main one is the my 1600tp won't idle anymore!!! Was bouncing through the dunes and pulled up next to my mate and engine stopped, and continued to want to stop everytime i tried to idle unless i rev'd it to stop it cutting out.

Also when i back off downhill with lowish RPM it starts to pop & fart (not fully back firing though).

Tried to adjust the idle air screw on the 34PICT Solex carby but made no difference. Screw in all the way... no change. Screw out all the way... no change!!!???

The idle solenoid is clicking with ignition and when connected & re-connected.

Performs ok when driving around, it's just the idling!!!!

Also noticed that she seems to be using a little more fuel than normal.

Could it be the fuel mixture screw?? Over fueling causing flooding on the idle circuit and also the 'over-fueling' when coasting at low RPM???

It used to happen a while ago but seemed to almost self resolve!!! Very Strange!!!

HELP!! Marty

PS New question at bottom

[Edited on 29-3-2005 by marty_08]

blocked idle circuit

stuffed idle solenoid, if it is the valve sort cut the tip off.

could have transient bowl of crap that gets in the way when you are giving it some

It could also be a vacuum leak. Check where the carb bolts on to manifold, or manifold boots (rubber bit connecting the top and bottoms of manifold), or where manifold bolts to heads.

Yes, the manifold rubber boots can crack causing the engine to suck too much air..... but it sounds like You have too much fuel.....

More Likely- IMHO:

Needle & seat not cutting out the fuel, so the fuel in the carby bowl over flows into the throat of the carby stopping an idling engine....

or the electromagnetic idling valve is blocked...
it has a tiny hole in it... make sure its not blocked...
as this will stop the fuel in the idling circuit in the Solex...


Best of Luck
Lee
http://community.webshots.com/user/vw68autobug 

to test lee's needle advice above, take off the filter and see if at idle fuel is bubbling away in the carb. other wise i would also say, with my limited exp, idle circuit or air leak stuffing idel around. look at your book for the idle jet (in the RH side of my carb at least), puff out the crap. can also drain bowl. for air leeks feel and wiggle fittings between carb and heads. if you can find a leak at the carb to intake gasket, the rubber boots, ect, fix it too.

Definately leaning out on decelleration..
Pull out the idle adjustment screw and blow it out with compressed air...(quick fix but could work) or pull it apart.
gotta be sand in the idle circuit.

If its popping and farting on overrun then its safe to say that the idle circuit has shit in it.
Overfuelling from a flooding needle valve would present as crappy running just about all the time short of WOT.

You have been for a fang on rough ground and probably have stirred up some crap in the carb.

Take off the air filter, rev it up a fair bit, then hold it WOT and quickly choke off the top of the carb with your hand for about 1 second, holding it WOT and let the engine clear out and rev up again, choke it again. Do this repeatedly but dun let the engine revs die right down or it will stop and be a bastard to start.

This is affectionately known as an "Italian Tuneup" and is particularly succesful with Holley 2 and 4 barrel carbs that are quite prone to getting rubbish in the idle circuits.

If it dun work on your engine then you'll have to remove the carb and give it a thorough cleaning.

L8tr
E

Oh cool, I was gonna post with exactly the same problem on my '74 twin solex bus. I was previously told about 'crap in the idle circuit', but wasn't sure where that referred to. I take it that that means in the carby itself then?

Thanks,
Aurel.

Thanks guys that's starting to make a bit of sense now!!!

I only just pulled the bloddy thing apart a month ago and put a kit through it and compressed air'd the whole carby!!!! But it did the same thing when i put it back together!!!

I'll try it and if it doesn't work i'll just have to through on the twin 40IDF webers i got the other day!!!!!

Which leads me to another quesiton that i want to ask........
If i go twin webers will i have to change to an electric fuel pump (eg holley red or blue)?? Or will the original be sufficient for the 40IDF's??? Anyone had experience with this????

John Muir says in the idiots guide that he has run twin webers on standard fuel pumps with no problems at all. Whilst Keith Seume says in the 'Aircooled VW Engine interchange manual' that the original will possibly flood at idle and starve the carby's with RPM. Who's Right???!!!???

Marty


[Edited on 29-3-2005 by marty_08]

Think of it like this.
The Webers will not use significantly more fuel that what you are using now unless you decide to rev the shit out of it, which will kill it, or plan to do plenty other tuning mods.
So if it copes now it will cope with as many Webers as you bother to mount. Knock yaself out and fit 4 of 'em!

A Holley electric pump is just expensive overkill and unnecessary.

Who is right? They both may be. Depends on what has been done to the engine really but iffen its closer to stock then it should be fine.

Webers will usually cope with fairly high fuel pressure, say up to 6 odd psi but I dont know what the original kraut pump delivery pressure is.
A simple malpassi or holley fuel pressure regulator set at around 3 or 4 psi or a even simpler regulated electric fuel pump delivering the same will solve the problem if it (flooding) actually occurs.

I tend to doubt that tho.

Best of luck M8
l8tr
E

That's all the encouragement i need Tas!!!!

ON THEY GOOOOOOOOOOOOO!!!!!!!!!!!!



Marty

Good stuff dude.
have fun with them!
L8tr
E