Carb troubles

Post by **selimg** » 23 May 2008, 14:03

I recently got an '86 T25 and it ran fine when I drove it home to London. But when I went to take it for an MOT it wouldn't idle properly and would just cut out unless I pressed on the accelerator and kept the RPMs at around 1500. It also backfires now and again but is fine at higher RPMs and was smooth on the motorway ride home.

When the local mechanic took a look at it he said there was something wrong with the carb and that a replacement would have to be sourced and fitted. Is he right and I need to get a new set or could I just clean the carb and play around with the idle settings?

If I do need to get a new carb then where is the best place to get a replacement for my model and what extra bits do I need to bolt it on?

I'm hoping to get this done before heading out to Le Mans so a place that ships quickly will be helpful.

The engine is a 1915cc water cooled petrol manual. So I can't give you any other details as the van is in the shop and I'm still a newb with all this stuff.

Thanks for any help.

E D I T: Yeah I found out it's water cooled, silly me.

Post by **clartsonly** » 23 May 2008, 14:31

I havn't got an Aircooled, but dont they have two carbs? also I thought that they stopped making Aircooled before 1986?

Get a second opinion, I think "you need a new carb" is a bit of a cop out.

backfiring not idling, and not very smooth running could easily be electrical like plugs,leads, rotor arm, cap, coil or quite possibly timing. or even oil breather blocked, vacuum hoses, idle stabilization unit.

Post by **jason k** » 23 May 2008, 15:16

yeah aircooleds will have a pair of solex carbs (one at either end of the engine bay) and a watercooled will have a single centrally mounted carb.

at the front of your van how many grills do you have?
just the headlight one or a lower one as well?

Post by **selimg** » 23 May 2008, 18:26

Yeah I just got the van back from the garage and it's a water cooled engine with a Pierburg carb. The guy is definite that a new carb is needed and has been searching everywhere for one. I doubt he'd go through all the trouble if he wasn't at least 99% sure that's the problem.

I also contacted a VW mobile mechanic and after describing the same problems he came to the same conclusion.

I also took a look at the spark plugs and the electrodes are covered in a black sooty substance which, from what I've read, is caused by a rich mixture.

Post by **RedSquirrel** » 23 May 2008, 18:44

Could be the fuel filter (in-line under the body).
Check the rubber gaiter on the filler neck inside the wheel arch as these perish and you get crap in the fuel line.
Also the carb reservoir could probably do with a clean.

Post by **trickydicky** » 23 May 2008, 18:46

Refurb the carb or if your mechanic is any good buy the kit and get him to do it, not a big job.

Post by **chippieshaun** » 23 May 2008, 19:04

I had the same problem......same van , same carb.
Would stall every time i braked and couldnt keep the revs up.
Took it to the local garage and they cleaned it up up and now seems to be ok.
To be honest , it was the second time that it happened to us , so maybe a regular thing?!
We are getting LPG'd next month so think that will sort the problem out!

Post by **selimg** » 23 May 2008, 23:00

If it becomes a regular problem then wouldn't a new carb be easier than refurbishing the old carb regularly? I was planning on replacing the fuel lines as I've read that worn out lines can lead to very bad things.

Which brings me to another question which dia. hose do I need, 5mm or 7mm?

Post by **skell** » 24 May 2008, 09:29

gasket and gubbins kit for carb to clean it up is about 30 quid, weber replacement about 300.... I got a very grotty looking 2nd hand pierburg when I fitted my replacement engine, spend hours cleaning it and it has been perfect since (3 years). If there is a lot of crap coming from rotting petrol tank or fuel lines then they will gunk up a new carb too.

With a new to me van I always remove petrol tank to check its condition and replace all the hoses, if they are original they will be "feck" by now

google gower and lee for carb repair kit

Post by **phade** » 25 May 2008, 14:28

I would also check your fuel hoses (all of them !!) and fuel filters for the following:-

- Fuel filter: sediment (or just replace it anyway)

- Fuel hoses: cracking, chaffing, fuel leaks.

If you need to replace any fuel hoses, avoid the cheapo rubber hoses (especially from GSF) since they will chaff and crack within 2 months. You can easily get synthetic yarn fuel hoses from your local motor factor. On my 1982 Aircooled campervan (the last year that Aircooled engines were supplied with the type 2 T3) they are 1/4" from the fuel tank to fuel filter and 5mm everwhere else.

I hope this helps

Post by **selimg** » 25 May 2008, 19:32

I just ordered some fuel hoses off JK but I got the 7mm dia. ones as that's the dimensions the wiki gives. Also got a new fuel filter so those will be changed aswell.

I found a refurbed carb off ebay for £140 inc shipping and decided to get it because it was within my budget and it doesn't hurt to have a spare. I could always sell it on if I really don't need it.

I'll also take a look at the tank and see it that will need a bit of a refurb.