I’m so screwed

[swede]

I taut it was an easy job to change my motor but there have been numerous problems so far.

The motor I put in is a European /118hp / 1800cc with manual choke and it seems to be in good condition. I have it up and running now but it won’t idle without 30% choke.

I have cleaned the carburetor (Weber 34 DMS) and checked that everything is working properly, so far I only found a small air leak in the carburetor axel seal but it’s very minor and was only detected by using starter gas (propane).
I also checked the ignition (Marelli S147) with the strobe light and found it was uneven on some cylinders so that needs some attention too.

Is there anyone here that might have more suggestions what to check?
Its starting to get critical since I’m going to a Italian meeting 1st of May and there is no way I can go like this.
I appreciate all information you all can give me so that I can resolve this quickly.

[So Cal Mark]

by closing the choke you are enriching the fuel mixture. If you don't have an air leak, you may have a plugged jet in the carb or jets that are too small

[Kevin1]

Start with fixing the ignition system, since you say it isn't working right. All you'll be doing with the carb is trying to compensate for a bad ignition. You'll never get the carb jetted and adjusted correctly if the ignition system isn't right first.

[sptcoupe]

Since when you dial in 30% choke you are both enriching the mixture and presumably increasing engine speed, I would look at the idle jet as being too lean, clogged, or both (assumming the timing is not way off). What idle speed is the engine at when you have the choke closed? If it is around 3000 RPMs and that's when it runs, then the idle jet is where I would look.

[swede]

Thanks guys your information is pushing me in the right direction

Yeah I will try to get hold of ignition parts tomorrow if the shop is open.
I can have the motor running if I keep it above 1500rpm when its warm and without choke but I will leave the carb until the ignition parts are changed.

What will happend if the carb floter needle dont close 100% ?
Will that make the carb overfilling and contibute to this problem ?

Is there anyone else here that are using a Weber 34 DMS ?
If so, what jet size dose it have ?

[racydave]

Its not unusual for a timing light to show fluctuations, it could easilly be the light! I would not assume anything.

[skumandeth]

Thanks guys your information is pushing me in the right direction

Yeah I will try to get hold of ignition parts tomorrow if the shop is open.
I can have the motor running if I keep it above 1500rpm when its warm and without choke but I will leave the carb until the ignition parts are changed.

What will happend if the carb floter needle dont close 100% ?
Will that make the carb overfilling and contibute to this problem ?

Is there anyone else here that are using a Weber 34 DMS ?
If so, what jet size dose it have ?

If the float doesn't close all the way it will flood over, causing hard starting, and a very rich smelling exhaust but would not cause the problem you are having. Now not being completely familiar with your particular carb, I'm not sure if it has an idle shut-off solenoid (small cylinder with a single wire coming out of it, should have power when ign. is on) if it is not working correctly it will keep the idle circuit from opening. It's purpose is to prevent dieseling. Jet sizing has nothing to do with your idle, the jets are strictly for part to wot operation. The first thing I would try (after making sure ignition system is timed right and working correctly) is get it warmed up, choke off, and it might take feathering the throttle to keep it running, but on the bottom of the carb, there should be an angled screw with a spring under it to keep it from turning on it's own. Slowly, turn this screw out ccw (it is the idle mixture adjustment) this will enrich the idle mixture, if it seems to have no effect back it all the way out, use carb cleaner and try to clean the port out(the port in which it gets it's fuel is in the bottom of the bowl and very small so is very susceptable to small pieces of dirt and debris. Then reinstall the screw till it bottoms out(do this lightly as the needle is very easily damaged) back it out 2.5 turns and see what happens, if it idles now slowly adjust till it smoothes out 1/4 turn at a time. If this doesn't help I would say either you have a major vacuum leak, cam timing is out(unlikely), or your going to get real intimate with the guts of your carb, as it will need to be removed and cleaned out thouroghly. Hope this helps

[swede]

The weather is great today, warm, sunny and not a single cloud insight

Major discovery today, the distributor cap is the wrong type so that might be one of the reasons for the strobe light to fluctuate. That distributor cap was put there by he former owner and I really him rigth now.
I have been to the parts dealer today and will get all ignition parts on Friday

I have found information on my carb at http://www.artigue.com/fiat/pubs/CARBUR ... %20DMS.pdf and I really need to read true that document and clean the carb totally for a second time.

I will keep you all posted when the new parts are in place