Club 80-90 Forums

OK, I have moved forwarded but still not solved the flatspot..

I replaced the vacuum advance without removing the dizzy with much cursing after working upside-down trying to get it connected for 15mins. Replacement unit came from TT automotive in Loughborough and cost 30 Quid which is good bit cheaper than Brickwerks which is the only other place I could get one. They surprised themselves by having them in stock! This fixed a definite problem with an air leak / advance. As I had been messing with the dizzy I had it timed by Farnborough VW centre (01252 521152) as I don't have a strobe. I have no affiliation with this garage but they were great - he adjusted the timing for the price of a beer and it was rammed with T25s and the impression I got was that they know their stuff.

Next I changed the fuel filter which was fulll of crud. i was convinced it was causing the problem but not so. HT leads, rotor, cap all <2K miles so don't think these are the problem.

Still got a mid range flat spot when I put my foot to the floor @ ~2500rpm. I suspect the carb is at fault (accelerator pump?) but as its perfectly drivable I'm still going to Norway next week!

Any suggestions as I will be logging on if things go pete tong?

if your going from 1/3rd throttle to full you need various things to work.
transfer jet
second venturi auto throttle butterfly opening.
advance
fuel

Sounds a lot like a blocked intermediate jet... good going, resolving all the other items, elininates lots of teeth sucking!

The fact that filter was clogged might also point to jet block..

There should be an old tried & tested trick in the Archives for clearing them in situ... will try to find it.

NB. Time JK started 'qualifying' that silly 009 advert.. enough peeps have been fooled and wasted years due to those goddam things. Irresponsible IMHO

From the Tech Archive forum: http://archive.club8090.co.uk/viewtopic.php?f=2&t=36598&" onclick="window.open(this.href);return false;

If the mid-range/intermediate jets are blocked then they are blocked, or intermittently blocked, carb cleaner is not a substitute for cleaning the carb out... not magic, it just removes varnish!

Either manually disassemble and clean but don't go rooting about through the jets with anything abrasive!

Or try this: Air filter off, engine running, leather glove on hand (Or not!), get it just above idle coming onto main jets and as you whack throttle open, choke the whole intake with hand just as it tries to rev up madly, remove palm of hand just before it dies. Repeat. Repeat.
Suction will very often drag dirt through jets or upset them, so if it gets better or worse, noticeably, that'll be muck in your carb.. if not fully resolved, disassemble and clean thoroughly...
If you can't feel a strong suction on your hand then not doing it right... vary throttle/revs at which you block it to cover as wide a range as possible. Don't worry if you stall it a few times, just clear the flooding and try again, it's a knack, but you need to know what and why you're doing it, not guess.
Worked many times for me with fixed jet carbs prone to blocking intermediate jets (main jet usually large enough to pass fine dirt)

Also,presume you have read this from the Wiki: https://club8090.co.uk/wiki/Fu ... rmittently

hi there i had the same prob with my van a while ago . after having the carb rebuilt with a rebuild kit ,then told it was ignition but after spendind a lot of time and money found out theres diffent diapham pumps for the carb
i put a diapham with the number 86 or 98 back in and it cured it the new was to lose