320/4 with starting / Solex problems

[E21-driver]

Thanks Peter, should be not a big deal then to check.
Another point, could it be possible, that secondary choke is opened during idle ? I mean, maybe there is too little clearance at the secondary valve bolt adjustment. Just an idea.

[Peter V.]

What do you mean by that?

I pressume that your chokeflap opens completly?

[E21-driver]

Hi guys,

The chocke flap opens just partly. I have never seen it opening to 90 degrees. But I couldn't run the engine so long, that it could warm up.
Just checked today ignition, it is correct. And installed an original Pierburg fuel pump, and also changed floater needle valve.
Same procedure again. The engine starts excellent, but after 2 seconds it produces black dust from exhaust and idle dies.
Has it something to do with the starter cap ?

Other question, I will try also a Weber 32/36 DGAV as next. I have one spare. Can I put it on the original manifold with an isolator ? Or do I need a spacer for it ?
Greets
M.

[E21-driver]

Hi guys,

Today, I have swapped my spare Solex into the car. It's not a 320 carb, but a 316 carb. I have completely cleaned it, re-jetted it with all 320 jets, swapped all new parts into it. Very good startup, holding idle almost by itself.
I had not much time today, but at the weekend I will warm the engine up and make some adjustments of idle needle and ignition timing.
The carb seems to be a newer version if the DiDTA, it has no CO screw. Instead of it, it has a fixed CO jet which is screwed in. So, I have only the idle needle for adjustment. I have set the needle three turns out, but maybe this is too much. Just for the right understanding, turning it in makes the air less and the gas richer ?
Mfg
M.

[Peter V.]

Wait, there you are wrong.

The second edition of the didta carb has no seperate idlescrew. For sure it has a CO (mixture) screw. You setup the idle with the barierscrew of the throtlevalve (Screw with no head).

[E21-driver]

Thanks Peter, you are right. I have seen it also in the manual. With this version, you have no other possibility. With the other version, I was told not to touch it. Let's try.
M.

[E21-driver]

Today, I have made some trails again.
The car starts well and it holds the idle.
I could drive it for some minutes, and could feel the two liters, feels good, if you were used to a 1.6.

But idle mode is still very black dusty. And sometimes when accelerating, is stucks for a moment, then accelerates well in upper rpms.
Could wrong ingition timing the reason? My Strobo lamp didn't work well today.
Or any other ideas?

[Peter V.]

It could be the right adjustment of the acc.pump or the advanced timing of your ignition is not good. Did you put the vacuumhoses at the right places?

[E21-driver]

I will check the advance timing again, when I get a better timing lamp from my friend.
The engine has three vacuum connections. One top at carb, second middle at carb and third bottom at manifold.
I have connected the advance timing at the top, as the original BMW manual says. The other both, are closed. I don't use them, because I don't use the fuel return valve and my dizzy has only advance timing (TSZ transistor dizzy from 315, same part no. is also used in 318i and 518i). Should be close enough to 320.

[white320]

Hi,

Just reading through the thread, and returning to the first post. My 320/6 had what sounds like a very similar problem.... The cause was air being drawn into the fuel line!?.... Could air be getting in somewhere?

You say the plugs are wet? Is this similar to a charcoal like coating?

Thought I would mention, as it could be something as simple as that?

Best

John

[E21-driver]

Hi,

Sounds interesting. And yes, it is definitely no water (white) or oil (blue) burning. It is black dust, so it is running too rich. But no problems in upper rpms. It takes the gas well now.

All fuel lines, pump and filter are new. So, from where else should it get air ? I have sprayed the whole carb and the brake booster hose with start pilot, no reaction.

How did you solve the problem in your car ? Where was the leak ?

[white320]

Hi,

My 320 had big problems in starting ... By cleaning the plugs and pouring small amount of petrol into carb, I managed to get her started, and she maintained at high revs, but dropped out at idle. Again, looking at the plugs... It's like you say " A black dust."

It was actually a good friend that noticed the fuel line hose resting against the alternator, that had created a split. I cut off the affected area and reattach, and that was it, problem solved.

The black dust surely must be a fuel and air mixture?

I would recommend checking all fuel hoses... Especially close to alternator and belts

Really hope you find the problem... Sounds very much like what happened to mine?

Regards

John

[white320]

ERROR!!!!!

Went to start her today and similar problem!!...

On examining the plugs the arrival black and wet...

Thinking my carburettor is opening up too much and flooding the engine...

WHAT IS THIS!!? Is it a tuning issue?

Disgruntled

John

[E21-driver]

John,

Open the carb and check fuel level. Is it too high? Check against manual value.
Then check floater needle valve. Is it closing properly? Blow into fuel connection with air and check by moving up and down the floater, if it is closing properly. And check floater distance against manual values.
Then check floater. Take it out and shake it. If you can hear some fuel inside, then it has a leak. If you are not sure, then put it into a cup of water for some seconds. If you see bubbles coming up, then change it.
Check also ignition timing with a timing lamp according to manual and the vacuum hoses if they are tight. Think you have the old dizzy with mechanical contact, so check proper adjustment of the contact and if it is burned down. Check also dizzy cap if contacts are burned. Check also valve adjustments.
Finally check vacuum hose of brake booster if it is tight. And also check function of the plastic non-return valve in it.
When the engine holds idle, then spray the carb, manifold and connections with start pilot or brake cleaner. Be careful, don't cause a fire by spraying on ingition parts. If the idle reacts on it, then you have a leak.
If these points are really ok, then your search will get more complicated (like mine is still black dusty, it is not burning oil or water).
Then you have to go on with the carb diaphragms.
Keep an eye on dust properly, is it white, black or blue coloured? Check inside the head if there is already some water penetration (white milky) and check coolant if it is really oil free or bubbling during throttle.

Murat

[white320]

Thank you Murat.

Just noticed that the oil has thinned from flooding with petrol!... Has this happened to you?

Best

John