Hi! Thank you for reading!
I have an issue with my Bella. '94, 903ccm, "electronically controlled" Weber 32 ICEV.
The symptoms are like this: when cruising, or getting up speed, she starts to stutter(/twitch?), like she gets no fuel. If I step off the throttle and roll some with "enginebrake", then step again on throttle she goes again, then starts to stutter again.
Or I clutch in and roll, rev the engine some with some throttle kicks, step off the clutch and go again then she goes again, then 5-10 seconds later starts everything again.
She does this for a 3-4 times, than she goes well again, for couple of miles.
Than stutters again. Sometimes even clutching in and revving does not help, the engine stalls. Then I have to use the starter for quite a while.

I replaced the carb gaskets, some O-rings, booster diaphragm, checked the fuel lines, checked the fuel tank (at least fuel gauge works now again ), changed fuel pumps diaphragm, but still does it, even with full tank.
I have a VAZ/Lada fuel pump on her from the beginning (84400km and 2013). Now she has 125900km.
With the VAZ pump she goes at least, but lately as described. The original fuel pump pumps nothing, though it was re-newed. :S

Fun fact is that I had a trip to Austria from Hungary (my home country), and the trip there was about 440km's, but she haven't done this on the way there, not even on highway where tempo was constant 110km/h, and had some many km long uphills. But before, and after she misbehaves, sometimes quite frequently.
So I start to get clueless.

Suspects are the fuelpump pushrod/camshaft combo, fuel pump, and the floater(?) jet (the one with the ball valve) I got with the repair kit for the carb. The original is 200, and the kit has a 150 jet, but I left the original in the carb.

Anyone had similar problems, or heard such? Would be great if she'd run well again.

hmm that is a new one on me. i would check for vacuum leaks. (we had one on our marbella with the electronic carb) again as you said check the float level and see if it is over fueling, the float may let too much fuel into the float chamber and it may be over flowing into the inlet manifold.

its possible that it could be a spark issue.. maybe the crank position sensor is not reading right. out of intrest what ECU are you running?

it has been a few years since i have had a marbella, so i am going on what i remember.

I have sometimes vacuum leak, but that makes just the engine lamp on dashboad light up and beep.
Than I guess I change that jet out, since the one in repair kit is smaller (150) than the original (200).
I don't think it's ignition, since when I clutch in and kick some throttle than it revs nicely.

I'll check the ecu and let you know!

Dragon Man said:

out of intrest what ECU are you running?

Click to expand...

Here's the ecu, I hope it is visible enough

yeah its the same ecu i had... like i say, check for split pipes. one on the evap system always gave me trouble. its the funny diaphragm thing that has a small pipe going into it and 2 pipes that look like fuel lines.

Any experience how can this carb changed to a "stock" carb (like Weber 30 DIC, 32 DAT), getting rid of the active carbon filter system AND keeping the electronic ignition?
I took the airfilter house down, and saw that on the top, left lower side, there was a stuff loose as hell, a round stuff with 1 cable on it, probably a solenoid inside, with 21mm hex for tightening.
I screwed it back and tightened as I dared , we'll see tomorrow how things are at a test ride.

Well, update time!
I had a trip today, back and forth 250km. And I got some money too,
so to go for sure, I got a new LADA/VAZ fuel pump too.
The nice red one.
Since at the end there was no fuel at all in the filter before the carb,
I had no choice, I replaced it on the road.
It was worth

And found another reason why my engine slowly looses oil, while she runs without smoke nor smell This crap is/are between the head and the fuel pump.

I tried to post 2 short and small video, but somehow it seems to not work.