I originally posted most of this in the OLLR forum, so forgive repetition if you frequent that place - I need a wider audience's advice! :lol:
My 2.25 petrol has had some issue with rough running. I have replaced ALL the ignition components (some twice :roll: ) right through from the battery to the plugs, all are correctly set up for the engine and unleaded petrol, all the timings are correct and I am pretty much convinced that the entire ignition system is as good as its going to get!
The running problems I am sure have been carburetter based, Zentih 36IV. Initially these where:
Coughing and spluttering on hard accelleration.
Repeated pushing the accellerator on and off hard would cause backfires.
Stalling / cutting out at idle.
Smell of petrol in carb after cutting out - flooding or over-rich running assumed.
No amount of adjustments helped. I stripped the carb down and de-coked it and rebuilt without replacing anything and got it running better, but still minor versions of all of the above.
I have today stripped down the carb again. I replaced the valves and injectors and pretty much used up a whole rebuild kit. I also replaced the float and set it to 33mm as per book, between top of float and gasket. Now in the book, the pictures show the floats as parallel to the face of the body, but in the real world I found that to do that would mean bending the flat shaft that the floats sit on and I didn't want to do that as it would throw them out of line with each other. I only bent the centre adjusting tab as per instructions to set the height and I took the measurement from the highest (lowest when right way up!) point on the float, again as per instructions. I also replaced the diaphragm as the old one was very worn. I also replaced the pipe from the carb to the dizzy for the advance.
All reassembled ok and refitted. She fired up straight away and the initial problem and reason for the rebuild was cured! No more stuttering and coughing on accelleration, smooth through the range and a higher top end rev! Great stuff.
Took her out for a test run and seems like bags more power and smooth acceleration. Really pleased so far. Filled her up at the garage (to which I am getting the impression she does not like) as she wouldn't start! Again!
Pumping the accelerator got her going but she struggled to tick over, limped out the forecourt and stalled again. Fired her back up and again away she went, but as soon as you took your foot off the accelerator, revs dropped and she stalled.
I adjust the throttle stop and got her going again. Revving fine, running fine and idling fine for a few minutes maybe less, before faltering and the cutting out. Re-start and/or heavy revving is producing black smoke!
Any idea what's wrong? It's driving me nuts now. It must be the carb as nothing else has changed on the vehicle and the black smoke is definately new! I am wondering if the float levels are wrong thus starving the carb, but then how do I alter them without distortion?
I have had some suggestions already but would be grateful for any further input before I take it to bits again!
I am beggining to think it maybe easier to just junk this one and buy a new one altogether...... :?:
H E L P 
