Gungy and dripping Stromberg
 

Hi There

I'm a carb absolute beginner; the other day the 144 (single CDS 175E) was fine, then went to start up again later in the day and nothing, would not fire at all. After checking the ignition was fine, made way to the fuel - plenty getting to the carb so not a pump problem.

Took the air filter off and just stared into space!! what's that? what's this? that seems a bit gungy......then happened to move the piston upwards and it turns out it was sticking. car runs fine now....so question are:-

1. is a carb dismantle and clean easier than most think?
2. can I clean it without taking it off or apart?
3. are these exchange services successful and who can you recommend?

The dripping bit of the title, refers to me (without knowing WTF I was doing) unscrewing the brass 4-holed plug from the bottom of the carb and tearing the perished rubber O ring....

One more question for luck - can a drip of petrol on a hot manifold ignite???

cheers now

Take the top off and fit a new diaphragm, very cheap. Clean the piston with neat petrol. NO ABRASIVES. Take care not to bend the needle. Fit new O ring. There should be a splash plate under the carb which prevents drips onto the manifold. Neat petrol is surprisingly hard to ignite but not worth the risk.
Don't pull the carb apart if you don't need to as it all has to be aligned properly when it goes back together. Keep the outside clean with an old toothbrush and carb cleaner, oil the pivots etc.

Hi Billy,

For that sticking thing you're experiencing, there's no necesity to take the whole carb off. It seems that you have a build up of gum on the needle and perhaps in the aperture of the jet.

It is quite simple to take the needle out of the top, as you say, by undoing the 4 screws and lifting it out together with the diaphram. You may find that the piston (plunger) has a build up of gum around it too which could be preventing it moving properly. While you're in there, there's no point in putting back in an old diaphram; they hole extremely easily and you should buy a couple - one for the replacement and one to keep in your door pocket for spare!

Whatever you do, don't be tempted to rub the needle with anything; the brass is extremely soft and you can change the profile very easily even with a very soft cloth. You should use carb cleaner and soak the gum away. If there is any sign of scoring on the needle, just order a new one. Burlen is very good for carb spares.

You can look into the jet from above once the piston has been removed. Again, don't be tempted to poke the brass with anything to clean it out.

You can clean the rest of the chamber out with carb cleaner. Don't worry about getting too much into the manifold - it evaporates quickly.

It is very unlikely that the jet has moved or has been moved! If it isn't centred properly, the needle won't drop properly without fouling on the jet thereby not letting the piston drop properly. But if you can lift the piston and it drops with a good "clink" onto the bridge, then it's fine.

It's good practise to occasionally peer down inside the chamber when you periodically take the air cleaner off to see if there's a build up of gum in and around the needle. Actually, just spraying carb cleaner down there without taking anything apart can usually sort things out.

big big thanks to you both - I got a variety of O rings from my local (brown apron wearing gentleman) motor factors at lunchtime (Roy's Autos on the Wells Road in Bristol if ever you're stuck in Bristol) and some carb cleaner, so will try and tackle this tonight

I note the warnings about soft brass and softly softly approach....

Biggest bother is getting the lid off, as one of the four screws has properly rounded off - will have to extract it and find a suitable replacement in my random things box

Billy - as all the others say, but don't be daunted, its only screws. Try to rebuild the fuel-injection system on my 164E, a completely different animal to set up properly.

However, I have just rebuilt both CD175s on a friends 164 because I found the same problem as you (although this car had been standing a bit). Firstly, its far easier to take the carbs off the manifold so you can dismantle them in the warm light comfort of your kitchen (send Mrs to bingo that night - they will stink!). Definately replace that bottom O-ring - when they perish they empty the float-chamber contents directly onto your manifold! Unscrew the 6 screws holding the float chamber on and then carefully remove the float-retaining spindle and undo the nut on the fuel-entry tract - behind it you will find a very small filter. Both of mine were gunged-up completely and prevented any fuel entering the carbs despite a new fuel pump.

Re-assemble with new gaskets and bobs your flippin'. Don't do anything to those needles though (except carb-cleaner) - treat like glass.

P

brilliant site

www.zenithcarb.co.uk

they list 'kits of this' and 'packs of that' but actually if you give them a call they will sell you as little as you need

I'm getting the 4 screws that hold the lid on the Stromberg as 2 screws are rounded out.....

I now realise this is the same outfit that SwedishandGerman was referring to Burlen......

as you were!!