Thanks Roy for good answers and adwice.
I'll try to explane what I ment about "shooting". You are right: The engine spits back through the carbs when touching trottle. And the engine spits back through the carbs with airfilter on and without airfilters, its the same.
O.K. well that does seem to suggest the mixture is very lean.
The engine run quite well at Idle speed, just a few "shooting", spitting back at Idle speed. But I have to turn the Idle mix screw approximately 4-5 turn unclockwise from seated if the engine shall run at Idle speed, without spitting back through the carbs.
For Weber carburettors which have coarse threads for the idle screws, 1.5 to 2 turns out should be about correct, so if you are having to use about 4-5 turns then it is much too weak even idling. That suggests an air leak somewhere, so you need to check this first. The idle system provides the transitional period over to the main system and if the idle is very weak, then the transitional period is going to be poor or non-existant.
After your adwises I have change to new spark plugs BP6ES, new coil and leads. And after running it a while a checked the spark plugs and it was very white. So I asume that the engine Get lean mixture.
I have blanked all vacumhoses to eliminate vacum leaks. I have also checked the Distributor and it's alright.
That is good and sounds correct regarding the weak mixture. But you may have air getting in elsewhere such as the manifold joints or the throttle spindles on the carbs. or even a porous manifold casting. The best way to check the system is to connect a vacuum gauge to the inlet and see what reading you get when idling. It should be around 21 inches of mercury. If it is much lower let's say 15 inches (or even lower) then you have an air leak somewhere.
Here are som spesifications for the carbs: the Main jet is 145, the air jet is 180 and the Idle jet is 50. The venturi is 40. I don't know exactly what you mean by Emulsion tubes?
I have also checked the float level, and it close at 8mm.
Since the Weber 40 DCOE not where standard fitment on the 2.2S, do You know which Weber that where standard on the 2.2S?
First the venturis can't be 40 in a pair of 40 DCOE carbs., they would have to be smaller. Possibly 34 or 36mm? And what auxiliaries are fitted? 4.0 or 4.5 or what?
To have 40 venturis you would have to have 45 DCOE's.
Your float level setting sounds too great. I would suggest 7mm since these are not new carbs. The higher float level will help richen things a little. The other jet sizes don't sound too far off although the main and air corr. jets are for the main system and a lot depends on things like which emulsion tubes being used as it is the combination of emulsion tube, main jet and air correction jet that sets the emulsification parameters throughout the rev range which is so important. The emulsion tubes are one of the most critical parts in getting the mixture right yet one of the most difficult items to select. However, this will only come after you have an air tight system and good idle.
As for the Murena 'S' that had twin Solex 40 ADDHE carbs. but that is not important since you can set up Webers or Dell'Ortos to do the same job.
I have read that If you have to turn the Idle mix screw more than 2,5 turn unclockwise from seated the carb have to small jets. Therefore I have ordered new main jets, 165, to eliminate lean mixture.
No, you do not really understand these carbs. I'm afraid. They are difficult to set up properly even for the experts so guessing sizes will just waste time and money. You have two systems in these carbs. The idle system and the main system. (well there is the starting system too, but we can forget that in this discussion)
The idle system consists of the Idle jets and holders and the idle screws. The holders are like small emulsion tubes for the idle jets and the combinations have to be correct. The main system, as I described above, consists of the emulsion tubes, main jets and air correction jets, and again the combination is very important to get the correct emulsification of the fuel throughout the rev range, plus the pump jets and bleeds have to be right in combination with the main system to provide the enrichment on sudden opening of the throttles and also provide top end enrichment at full or near full throttle.
If you have to turn the idle screws out to 4-5 turns just to idle, all you have done is to provide more fuel mixture at idle, please note: NOT a richer mixture just more of the same, but the moment you try to open the throttle it will go weak again, as the system is still weak - all you have done turning out the screws is compensated by adding some EXTRA mixture whilst idling. Increasing main jets does NOT alter the idle system, only the main system. You can't richen the main system to compensate for a weak idle! These carbs. simply don't work that way. The main system is not in play until about 2,000 rpm upward.
I also Wonder If I should change the Idle jet up to 55 too, so that I might just turn the Idle mix screw from 1,5 to 2,5 turn unclockwise from seated. What do you think? Is there some sizes at the jets that belongs together? If so which do you recommand?
Thanks again for good questions and good adwises.
Best Regards
Gjermund
Before you start changing idle jets or any other settings you need to check the manifold vacuum reading and eliminate any air leaks, which it sounds like you still have. When you definitely have an air tight system then you can see how it runs and whether it needs resetting. However, these really need setting up on a rolling road, and if done well will be worth the cost as you would never achieve the same by the hit-and-miss guessing method. What is more is that you would only get charged for the actual jets or emulsion tubes used even though he might have used several sizes from his stock before settling on the right ones. If you tried this you would have to buy all these and the unused ones would be a waste!
One final point - what mounting system is being used? These carbs. should not be bolted solidly to the manifold. They should have a set of 'O' rings between the manifold and carbs. and the fastenings should be either with Thackeray washers or Cosworth mountings and the locknuts should be tightened so there is about a 1mm gap all around. The 'O' rings do the sealing and the carbs. are flexibly mounted to help avoid fuel frothing. Just the same as on the 'S' (or any good Lotus twin cam set up for instance).
Roy