popping carbies

phil Seriously Crusin Dubber

128 posts · joined Mar 2005 · 21 May 2007, 4:24 pm

#592572

hey fellas!
can anyone help me with this ?
for some time now my car has been backfiring through the carbies when cold....runs great when warmed up.
it's a 1640 t1 engine with dual kadron setup and cheapie extractor exhaust, 009 dist.and compufire module, otherwise standard...carbies seem balanced with throttle plates? equal and mixture screws turned in till stumble then back 1/4 - 1/2 turn.
any ideas?

56astro Custom Title Time!

1,772 posts · joined Aug 2002 · 21 May 2007, 5:03 pm

#592574

Have you tried to do a search?

There are heaps of threads about "popping" through carbies.

VW car, VW engine ...... keepin it "real"
35MPG on 101.3kPa

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 · 21 May 2007, 5:32 pm

#592576

Read hear

http://www.lowbugget.com/main_page.html

basically -

Popping out the top of carb:
Incorrect Jetting.
Clogged idle jet.
The distributor is not advancing correctly
incorrect accelerator fuel squirt adjustment.
Small main jet.
To big of venturies.
Check your linkage, make it open the carbs not close or hold them open.
Is the timing correct? I do not recommend setting your timing at idle or static.
This is just for getting it to start and should be set afterwards with a timing gun set at full
advance.

My guess is to lean as it goes away when warm

Futue te ipsum!!!

Oasis Going alone...

1,806 posts · joined Jul 2003 · 21 May 2007, 5:35 pm

#592577

Could be the linkage. When the engine "grows" when it gets hot the linkage comes good which might explain what it does only when it's cold, especially with Kads. my 2c

"Tell him 'We've already got one'"

ian.mezz I never said, I could write or spell

3,913 posts · joined Sep 2004 · 21 May 2007, 8:10 pm

#592615

I had a bug do that and i found that i had a few inlet tappets that needed adjusting:o

😂🤪😂🤪😂
car forums. where a lot of peoples good intentions end up taking a good old car off the road forever never ever to see the road again. 🥲

phil Seriously Crusin Dubber

128 posts · joined Mar 2005 · 21 May 2007, 9:48 pm

#592648

thanks all.
did a search....nothing new there.
i will double check for air leaks, then
i guess i will richen mixture a little and see what happens...then maybe advance? the timing a little.
met a mechanic at work a couple of weeks ago who believes the quality of fuel is responsible...says FI systems can cope with variable fuel better than carb...says quality of fuel has been poor for a couple of years?

ancientbugger Custom Title Time!

1,986 posts · joined Mar 2004 · 21 May 2007, 10:04 pm

#592656

I'd guess your choke (if you have one) isn't working properly. In colder temperatures the cooler air would be more dense and so you'll be effectively running lean but as the engine warms up so would the air going into the engine.

Craig Torrens 6 times Australian, 7 times State Hillclimb Class Champion

8,040 posts · joined Jan 2003 · 21 May 2007, 10:04 pm

#592657

your linkage is out, you just need to adjust.

Craig Torrens 6 times Australian, 7 times State Hillclimb Class Champion

8,040 posts · joined Jan 2003 · 21 May 2007, 10:06 pm

#592658

Bizarre wrote:My guess is to lean as it goes away when warm

How did you come up with this one ? :jesus

phil Seriously Crusin Dubber

128 posts · joined Mar 2005 · 21 May 2007, 10:13 pm

#592659

Craig Torrens wrote:
Bizarre wrote:My guess is to lean as it goes away when warm
How did you come up with this one ? :jesus

i thought this sounded ok?
no choke on kadron/solex kits, therefore a bit lean when cold..or is it an absence of enriched mixture when cold? therfore behaves as though lean until warmed up

phil Seriously Crusin Dubber

128 posts · joined Mar 2005 · 21 May 2007, 10:16 pm

#592660

yeah..thanks Craig..i thought i had linkages right but on reflection i have been tricked by them before

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 · 21 May 2007, 10:25 pm

#592665

Craig Torrens wrote:How did you come up with this one ? :jesus

VERY common sympton on Webers to "snap" out the top of the carb when idling on a cold morning if the idle jet is "just" lean.

Dont worry craig - one day you will understand. :alien

[ Edited on 21-5-2007 by Bizarre ]

Futue te ipsum!!!

plebs Casual Dubber

47 posts · joined Dec 2006 · 22 May 2007, 12:28 pm

#592741

phil wrote:thanks all.
did a search....nothing new there.
i will double check for air leaks, then
i guess i will richen mixture a little and see what happens...then maybe advance? the timing a little.
met a mechanic at work a couple of weeks ago who believes the quality of fuel is responsible...says FI systems can cope with variable fuel better than carb...says quality of fuel has been poor for a couple of years?

I had this just recently, bad fuel from a dodgy cheap station, I had to drain the tank and run it dry then refill with brand name PULP and all was well.

Stock as a rock and slooooooooooooooooow

Craig Torrens 6 times Australian, 7 times State Hillclimb Class Champion

8,040 posts · joined Jan 2003 · 22 May 2007, 9:07 pm

#592825

Bizarre wrote:
Craig Torrens wrote:How did you come up with this one ? :jesus
VERY common sympton on Webers to "snap" out the top of the carb when idling on a cold morning if the idle jet is "just" lean.

Dont worry craig - one day you will understand. :alien

[ Edited on 21-5-2007 by Bizarre ]

I hope so Barry :kiss

phil Seriously Crusin Dubber

128 posts · joined Mar 2005 · 22 May 2007, 10:09 pm

#592841

:blush