One idiot one solex, part 1

Post by **jtbo** » 20 Jul 2006 02:24 pm

This is about Solex cisac 34-34 Z11, I think it was 34-34

Because of our MOT system I need to fit carb back to car and I thought to look into carb a bit, check all that is stated in Haynes book and also what I have read from this board.

Haynes says that float height should be adjusted so that it is 33,8mm measure from seal to edge of float, while spring loaded ball is not compressed.

Well, I did measure and it was something near 50mm, so what does this affect? I would guess that it means lean mixture because of fuel shortage, but am I wrong?

So I did adjust it to somewhere near correct value, it was not too easy to get precise measure as spring in that ball is quite weak and my measuring equipment was not correct to job, but I think it is now near 40mm, but I did not like to adjust it too much as now already ball is compressed just when float touches that base where it is attached, so any more and it may flood?

This leads me to believe that whole float thing might be twisted by some previous repair shop, that has tried to adjust it wrong.

I have not yet installed this as I need to find my manifold that is somewhere in cellar under mountain of stuff

Anyway I would like to know if I have understood how this thing works correctly so I won't end up engine room covered with gas

Other things mentioned in Haynes were weight of float, which may or may not be in spec, I can't measure anything that light, then idle mixture base setting, that I did set. Also there was test for float if it leaks and there was no sign of air bubbles.
Magnetic valve would need new o-ring as current one is snapped, must be that I have tighten it too much at some point, but could not see much other problems, filters were ok and those things that has holes in them and are screwed to place seemed to be ok and no dirt there (3, one at top plate and two at center of lower part).

Also I cleaned thing as well as I could, but I have no possibility to use strong chemicals for cleaning so it could use better cleaning with gasoline and compressed air, however I don't like to mess with gasoline inside of house and neighbourgs might not like if I do that at parking lot so makes things bit more challenging.

Perhaps tomorrow I will fit it on place and do other MOT checks, so if you have some tips for this carb before that all is appreciated

Post by **Chris_C** » 20 Jul 2006 02:37 pm

You are right on the carb Jani, those floats keep the fuel bowl at a set level, so that air sucks fuel from the bowl, fast air going through the venturi picks up fuel cos of air pressure changes. For your floats to be that far out, you're fuel bowl level would have been 12mm lower than spec, which shouldn't (I think) make too much of a difference as the jets pick up from the bottom of the bowl in the Solex (again, I think, havn't played with that one properly)

The mixture shouldn't be affected at all, as long as the fuel level is always above the fuel inlet of the jets (those things with holes in I'm guessing!) Make sure you put those but in the order they came out, that is what was screwed (well, one of the things!) on Fake.

If the floats arn't set right, it can caused flooding on start up somehow (not sure how, but that is something propsed that my starting problem may be) but I should think +/- 1mm would be ok

Post by **jtbo** » 20 Jul 2006 02:53 pm

I was thinking if this wrong float height could do this problem where engine stops/runs/stops/runs (0,5sec per phase) when running low throttle, then there is little airflow and low level of fuel, maybe there has been trouble of getting fuel?

I'm not sure at all about that 50mm, it could been 60mm too, I did measure it quite harsly, but it looked to me that there would not been not much fuel at all in float chambers as even slight float rise would make that ball to move and I guess that is somekind of valve that shuts down fuel coming to float chamber?

But these are plainly guesses as I have still long way to understand fundamentals of carb behaviour, maybe some day I will understand this device too

Oh yes, I think two of those things with holes were emulsion tubes, jets should be located under them I believe, but I have no tool to access them as they are so far at bottom. But if you think that that problem might be because of dirt in jets, then I need to open them naturally.
There was also some very fine sand or similar at bottom of float chambers, I think this has come from trough ventilation system as there was just this hose hanging. I had filter there for some time, but it looked bit stupid so I left it out

Post by **Chris_C** » 20 Jul 2006 03:08 pm

TBH mate, I'd say it could be either of those, sand or float height, that is causing the dodgy running. I'm not sure how often the valve opens, but as it's the simplest one to fix, try just that first!

The float needle valve is really simple, it's not hard to have apart to understand. Basically, on the other side of that sprung ball bearing, is a needle, and that gets pushed up by the floats when the level gets to a set height, and stops filing the float chamber. This needle sits in another tube, when raised, blocks the tube, when lowered, allows petrol to pass.

I'd imagine the jets are attached to the bottom of the emulsion tubes in the Solex, however, haynes diagrams are cr*p for that carb!

Post by **jtbo** » 20 Jul 2006 03:20 pm

Thank you from help in this, I have this pic, I think it is not so bad?
(had text explanations too, but is now somewhere where I could not find)

19&20 are jets (maybe 58 too?) and 16&17 are emulstion tubes I believe, then that one other I did open earlier was 43

That wire 49 has never been connected and I really have not found any ground plug in my car where I could connect that to, but perhaps I make my own plug for that, I guess it is ground wire?

52 & 48 I really don't know what they do (well I know spring and that other thing, but what function those are related is unknown), but 54 is accelerator thing and I replaced that once.

Website · Post by **antiekeradio** » 20 Jul 2006 11:14 pm

if your float was so totally mis adjusted you would think that was done for a reason ....

on my 1.7 the fuel bowl just flowed over into the venturi.

the fuel level in the bowl does make a difference, think of bernoulli's law. when the fuel sits too low the venturis will have to pull much harder to suck fuel up to the takeup point.

On the float; I would really advise you to find a means to weigh it accurately. put it in a jar with gasoline first, for a day or so. then dry it off and measure the weight. sometimes the float is just much too heavy... this means that fuel has gotten into the foam material of the float.

the normal checking procedure (put it under the surface of warm water and watch for bubbles) does not work for such a plastic float.....

easy check: remember this picture!

Post by **jtbo** » 20 Jul 2006 11:47 pm

Thanks, must test that float test thing tomorrow.

My guess is that float has been adjusted with that ball bearing fully compressed, ie. they have put part upside down to table, taken measure and adjusted, this is wrong method and will give false information, I would say difference is indeed somewhere between 10-15mm and my float has even more wrong than that, which I find bit odd.

Luckily that thing is rather easy to disassemble even if it is installed to car so I can fine tune level if I can understand symptoms right, I guess this is hardest part

Better get some sleep, it will be 4-6 hours work with car tomorrow

Post by **jtbo** » 21 Jul 2006 04:46 pm

http://www.janiervast.com/kuvat/volvo/problem/

What do you think about this little crack? Is it going to be real problem?

It must come when I last time installed carb, I have perhaps used too much force to tighten those knuts, even I was not red then

I think it was something 15nm that was allowed, but that helps not much as I have no such tool that measures torque...

It is not cracked completely, there is little part where is no crack so it can be that it won't get any bigger, also I have some stuff that I might apply to outside, to make it seal crack, it would prevent at least air get sucked trough there, but it will not strengthen that part.

I remember when this part was renewed by carage last time, I think it was perhaps 3 years ago and it was not cheap, over 60€ I think, so I won't be buying new one at least...

Website · Post by **antiekeradio** » 22 Jul 2006 06:47 pm

personally, I would not reuse it.

sounds expensive though

are you 100% sure the surfaces are straight?? (manifold/carb)

15 nm is really light!!! perhaps there are some spring washers, these will not be fully compressed at 15 nm...

Post by **jtbo** » 22 Jul 2006 07:41 pm

I had to use that old one as I really have no cash for it, but if there is problems I try to put some of gasket stuff to it, that fixes everything, lol.
I'm not sure at all if those surfaces are straight, I have not checked as I could not even think about that possibility.
I did tighten bolts now to some not so very tight, but so that carb perhaps won't come loose, also there is no washers, but I don't think it has ever had those.

I did not manage to start car yet, but I better post to another topic from that.

Post by **jtbo** » 23 Jul 2006 11:43 pm

I did some research about this fuel level in float chamber and what it does affect, then I came up with this information and thought that might be interest to some in here too

What does it effect
What does this have to do with your float level? My friend Marc Salisberg at Factory Pro puts this in these simple terms : "picture a person sucking on a straw in a can of soda. Now picture another person sucking on a straw in the same can of soda but with a straw as high as a two story building. The person sucking on the long straw with require much more suction to get the soda up to his mouth." Now to clarify, the key here is the distance to the level of the soda in the can. Now picture the same scenario but instead with the carburetor jets instead of the straws. It is easy to see that the fuel flow rate can be greatly controlled with the adjustment of your float bowl thereby the level of fuel in the fuel reserve (float bowl). The higher the float level the more fuel flow at a given suction. The lower the float level the less fuel flows at that same suction.

Source was google cache from forum of :http://www.maxairengineering.com/garage

So it is very important it seems, can't wait to get my car started to see how adjustment affects to it. Just had too much other things to do today

Post by **Chris_C** » 24 Jul 2006 12:42 am

Thats a great analogy... and that now makes a lot more sense! Nice one mate

Post by **pettaw** » 05 Aug 2006 09:05 am

Yeah, Jani's found exactly the right clip. That's what it does, it doesn't really change the idling or cruise mixtures, but it majorly affects high throttle usage, and particularly the transitions to wide throttle openings, where along with the accellerator pump it controls how much extra fuel gets dumped into the mix, cos the higher up the emulsion tubes it is the more is gonna get sucked in one big lump rather than having to go through the holes....that wasn't a good explanation......anyway

Post by **schakal** » 05 Aug 2006 10:37 am

jtbo wrote:Thank you from help in this, I have this pic, I think it is not so bad?
(had text explanations too, but is now somewhere where I could not find)

19&20 are jets (maybe 58 too?) and 16&17 are emulstion tubes I believe, then that one other I did open earlier was 43

That wire 49 has never been connected and I really have not found any ground plug in my car where I could connect that to, but perhaps I make my own plug for that, I guess it is ground wire?

52 & 48 I really don't know what they do (well I know spring and that other thing, but what function those are related is unknown), but 54 is accelerator thing and I replaced that once.

first ,must say this whole thread is a great read ,top job lads

i was under impression that items 16&17 were jets and never seen 19&20 when i took my solex 28 34 z10 apart ???? can someone clarify this please???

also i heard people talking about getting bigger jets .
does anyone know where to get them from and
how easy are they to replace on a 28 34 z10 ????

Post by **jtbo** » 05 Aug 2006 11:22 am

Number 14 is idle jet, but I'm not quite sure. That is anyway where Haynes told them to be under lid number 21.

Then Jet sizes according to Haynes are following for B200K

Code: Select all

                      First stage            Second stage
Venturi                15                          27
Main jet (fuel)      120                        115
Main jet (air)        145                       130
Emulsion tube      ZN                         ZC
Idle jet (fuel)       41                          60
Idle jet (air)        100                        100
Accelerator pump jet 60

Maybe that has some use for someone too, oh yes B230K has main fuel jet 125 and it should make carb to behave lot better I have heard.