Thats alright mate... I was hunting for ages trying to find it on mine Actually... might get you to do me a favour if you wouldn't mind, mines been messed with over time, if you want to take things apart one day (;)) I'd be most greatful if you could tell me the jet sizes, and order. Mine were all in the wrong place!

(If you do, take them out one at a time so the same thing doesn't happen to yours!!!)

I'd be super greatful, but you do have to take the top plate off, so I don't mind if you don't want to.

I'm not sure what you mean by jets For example the sizes of air correction ( 9 ) jets shown at the first picture from the top are:

-220/F58/107;
-135/F56/115;
-70.

But if you need to know the main jets sizes ( 8 ) which are deep inside the carb than I'd rather not to mess with all that stuff under the plate (not yet)



By the way I've failed second test. Even thought I found the mixture screw still I can't adjust it properly. When it's fully screwd in revs dont seem to come down. I heard that propably the mixture screw is too big and I need the smaller one

Those numbers are what I'm after, as well as the ones main down (yeah, 8 ) Don't worry about grabbing them though if you don't want!

Sounds similar to what I had, mine was running super rich though (off the scale if you put some accel down, but just in on idle) I can check my jet sizes later, and we can have a comparision, I know mines at least on the scale and MOT passing, even if it's not quite right yet. There are a few guys on here who know some carb theory (I have some books on it) Pettaw helped me get mine sorted, basically someone had thought the jets looked a bit like lego, so had a play swapping them round

Nah, the mains are the last number on that series.
The deep bits in there are just casting inserts to hold the mains in, but the mains are the last number.

You've got 1 number on there, which is the idle jet. Would be useful to get the other idle jet number too. Should be like a 75 or something. And which was it opposite. Was it the 220 end or the 135 end?

Ahhh, sorry, I was reading the diagram wrong! Andy's right, that is what I wanted I'll go and look at mine in the morning, and see what mine are in there current passing spec state (although they sound very similar... so should just be the screw adjustment for you hopefully unless the idle jets are swapped)

please dont start screwing around with jet sizes before everything else is checked and double checked.

some people have spent countless hours behind advanced testing equipment to set up the stock values. you just can't "fix" an engine with an obvious fault like this with different jet sizes.


you might start checking for the commonly known problems with this carburettor;

- float shot; too much fuel gets in reservoir; flows over to venturis
- flange bent, air leakage


dismantle the thing completely and have the dry float weighed on a precision scale. more than 7 grammes = goner.

Hey Wouter, havn't seen you for a while. My bad, just sounded like an identical problem to what I had, and my jets had all been swapped what looked like randomly and definately wrongly. I wasn't suggested that the poster swapped all the jets randomly, just that we could compare sizes, check that they are the same now mines been on a gas tester and working much better.

Maybe you could explain the proceedure for the common problems you describe, I did the float check with someone talking me through what to do over skype, so didn't take too much of it in at the time, and couldn't re describe it. I am however trying to get the optimum float height details from Webcon for this carb at the moment.

Cheers, Chris

Wouter, Chris's problems are different, somebody basically messed up every single setting on this carb, in an attempt to get the car running, including swapping the jets around, altering the float height adjustment, fiddling with the secondary throttle plate settings, etc etc.

Chris only asked what combination of jets he had so that we could check that we've replaced the jets back into the correct places.

The mixture adjustment on the carb is in a strange place, its in the base. There's an angle piece that comes off the carb body, and there's a small screw in the base of it, and that's what adjusts the mix.

If he's got a CO of 5.5% then the carb is working fine, there's no air leaks. If it drives OK then I would say the float is fine too. Just adjustment is needed hopefully.

Hope we didn't confuse anyone

PS: If you could get the number off the side, then we should be able to get the definitive specs from Webcon UK and that would be most helpful.

Many thanks.

Oh OK I see. guess I'm one owner late with this warning then



jet sizes can be found on page 65 of the following document.

I dont think I have it in English, so this dutch version will have to do.
its comprehensive documentation on the 1.7


http://www.volvo300club.nl/v3m/b172k.pdf

PS if idle is solid and even at 5,5 % you may have hope it can be corrected by some tuning.

Yeah, I've got the english version of that book, trouble is that this is a Weber replacement, not the Solex original

do you have that english booklet digital?

Nah, I'm afraid not. Paper version only

OK, well, if you ever... you know how to find me