Club 80-90 Forums

I'm posting this, peppered with relevant keywords in the hope that should anyone experience the same problem, they may just find a solution here.

Some months ago I ran entirely out of petrol at a busy junction in the pouring rain with my five year old son onboard. Fortunately a sympathetic bay owner going the other way saw the situation I was in and towed me off. I returned to the car park I'd left it in the next morning and it started with little problem with a gallon of petrol poured in, plus a dash down the inlet bore for good measure.

However, I had noticed a definate drop-off in power, mild hesitation on acceleration and what appeared to be a speed governer at around 65mph (mine will normally do 80mph fairly effortlessly). Last week I replaced the main fuel filter near the tank but this made little difference, neither did new plugs and a non rev-limiting rotor arm.

Its worth pointing out that the Pierburg carb in fact has its OWN filter, almost unseen as its fitted right inside the brass fuel inlet pipe - cone shaped, and only removable with a screw around the same diameter.

Today I removed this and discovered it was totally crudded up with limescale/rust and with a careful wash in detergent and rolled between finger and thumb, it was clean once again. Refitted, power restored, smooth acceleration and no top speed limit. So, worth remembering if you have the same carb, don't forget to clean out this filter as well as replacing the one near the tank. If you tend to run low on fuel or run out altogether, you could well find your bus runs like a box of loose spanners. For reference, the float bowl was free of any muck.

An excellent posting young man

and a timley reminder for the wise

Put it in the wiki

and have a beer

Added: https://club8090.co.uk/wiki/Fu ... ting_carbs" onclick="window.open(this.href);return false;

CovKid wrote:Added: https://club8090.co.uk/wiki/Fu ... ting_carbs" onclick="window.open(this.href);return false;

nice

I'm having that beer too

Do I have one of them Pierburg carbs then?

My vans 1984 A reg 1.9DG

Sarah

You do indeed The WIKI link above shows the exploded diagram. Carb part number '2'. You need to pull off the hose from the carb (the one coming from fuel pump) and gently turn a self tapping screw that just fits inside the brass inlet pipe then pull - should bring the filter out. Chances are it'll look brown and be caked with crap. A good wash with detergent, Several rinces, rolling the filter gently between fingers should loosen the gunge and it'll be white once more. Dry, refit and hey presto!

You could I suppose dispense with it if you fitted your own fine mesh filter on the pipe but just as easy to clean it as I've mentioned. Very easy to overlook as its tucked away and you'd never know it was there unless pointed out. If its not clear you'll DEFINATELY have crap running and some weird symptoms. I've had this problem for months ranging from dying at junctions unexpectedly, insufficient fuel when tanking it (mine would just hold back around 60-65mph and not pick up until I dropped back to 40) and generally lumpy running.

hi covkid apart from the speed limiting you have this is exactly what our 2l air cooled is doing,ive had a quick look in the haynes manual and it says ours should have twin solex 34pdst carbs,i know its got twins on it but ive not checked which ones yet as the van is full at the mo,but would there be a similar thing on ours and if not any ideas what is wrong?

Cheers steve n liz

great heads up Covkid! just nipped out to the shed to check the carb i have on the spare engine and it was gunged up with crap.i will check the one on the van as soon as it stops raining.cheers Ben

steve n liz wrote:hi covkid apart from the speed limiting you have this is exactly what our 2l air cooled is doing,ive had a quick look in the haynes manual and it says ours should have twin solex 34pdst carbs,i know its got twins on it but ive not checked which ones yet as the van is full at the mo,but would there be a similar thing on ours and if not any ideas what is wrong?

Cheers steve n liz

I'll be perfectly straight here, I had a bay and a wedge with the twin carbs and always had probs getting them running right until I had them rebushed by Roger Ball at Clacton. Those twins are VERY sensitive to any air leaks. I'd seriously check for wear in the throttle flaps and consider getting them rebushed by any good lathe man and fit carb repair kits - THEN try and tune it

hi covkid thanks for the reply,are the throttle flaps the butterflys in the top of the carb? The left one on our van doesnt close all the way like the drivers side one does,is this right or should they both close.
We have a cnc machinist at work,what does this rebushing involve and where would i get the refurb kits from?
Also having looked at the carbs,i took the air filter assembly off and the filter is black and there is about 1.5mm of oil etc in the bottom under the filter which is obviously not good,any ideas?


Cheers steve

No its the very lowest flap. Rebushing involves removing the flap and spindle, milling the spindle to get it true and uniform, then fitting new bushes at each end for a snug fit. The guy I use makes them to fit the job. There can't be many of those twin carbs around that don't leak air through the flap spindles - unless they've already been rebushed. Gasket kits are still available to my knowledge but can't advise where. To be honest they mostly need new accelerator pump diaphrams and a regasket, the latter could be made from gasket paper with a craft knife and a carefree evening but kits tend to contain small o rings and so forth. Air leaks on the throttle flaps make it almost impossible to achieve even idling and all kinds of associated problems. You can check yourself by removing one carb and seeing just how much up and down (rather than in and out) movement there is. Even a tiny amount is enough to create problems and too often timing and other settings end up tweaked too far in an attempt to compensate, or at least get it to run.

Incidentally, back on the subject of that cone filter, I got a chance today on a run out with Chickenkoop to floor it a few times and there was no hesitation throughout the entire range right up to 80mph - just wound up like a T25 in good order. Nice to have it running properly again.

steve n liz wrote:hi covkid apart from the speed limiting you have this is exactly what our 2l air cooled is doing,ive had a quick look in the haynes manual and it says ours should have twin solex 34pdst carbs,i know its got twins on it but ive not checked which ones yet as the van is full at the mo,but would there be a similar thing on ours and if not any ideas what is wrong?

Cheers steve n liz

Hi, before you start rebushing carbs, just strip them and give them a good blow out with an air line. Even remove the CO screws, making sure you count the number of turns, so they go back in same place. Makes no end of difference. Change fuel filter at same time. Then get your local friendly garage to stick the pipe up the exhaust to check your CO and HC's...that will tell you if you got any air leaks. If you can't find a friendly garage then get your van over to Grantham
IAN

cheers mate il do that and give them a good clean at the weekend,is there any way to adjust the top butterfly on the left one as it doesnt close all the way?

Sorry for hijacking the thread covkid

cheers steve