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2.25 petrol (yes). Prior to a complete rebuild the engine had been starting and running very reliably, although with a lot of black smoke/rich. I'd fitted a Weber 34ICH overhaul kit last year while trying to find a fault that turned out to be the pump, which made no difference to how it ran. After the rebuild (rebore, crank polish, new bearings everywhere, valve guides replaced, seats cut etc) it started instantly and ran smoothly, although still rich. I checked the float level and found the level too low/measured gap too big by about 1mm, so corrected that and checked that the range was still OK. (But now wonder if someone had been in there before and set the level low in order to try and correct this problem). Followed the Weber instructions on stop and idle jet setting, no real difference. I'd given the bottom of the air filter a clean and oil change, so thought I'd check the top mesh. No problem found, but when I put it back on the engine was now running visibly clean and the smell of part-burned fuel gone. Off then for an MoT. It drove pretty well on the way over, but when the tester drove off to check the brakes it kept cutting out, and I thought maybe he was stalling it? When he came back he took it straight in to the test bay and didn't comment until after the test. He showed me that the HC had been over 5%, so had 'adjusted the carb' for me and got it down to 0.33%. Said 'it's the linkage' several times, and assumed he meant idle speed/cut out was due to some slack that he'd fixed. As for the HC levels, err, Ok, thought I'd got it sorted, but obviously the air cleaner wasn't the problem. Thing is that it was running terribly. Wouldn't idle, back firing on the overrun and would only idle with choke. So I'm thinking maybe the filter to carb hose had a blockage/collapse and so disconnected it at the carb. No difference. Then saw that the locking tab on the spindle was undone and the nut loose, what's he been doing because I hadn't touched it when I rebuilt the carb last year and it was locked then? Tightened that, no difference, but I don't yet know if it's been put together wrongly.
I'm now thinking maybe some dirt from the tank (which I'd cleaned out after the misfuel episode last summer) had dislodged when it was standing on end and being manhandled in and out during the rebuild. Somebody tipped me off about the neat little filters that solder onto the pick up pipe - bought one but haven't fitted it yet.
btw. Ig timing absolutely spot on 6 deg before tdc (high comp engine).
I reckon possibly two problems here. A. Running rich. B. Something happened as I drove it for the test and it's coincidence that the the tester drove it immediately afterwards.
Anyway, long post but trying to give as much info as possible.
I'm now thinking maybe some dirt from the tank (which I'd cleaned out after the misfuel episode last summer) had dislodged when it was standing on end and being manhandled in and out during the rebuild. Somebody tipped me off about the neat little filters that solder onto the pick up pipe - bought one but haven't fitted it yet.
btw. Ig timing absolutely spot on 6 deg before tdc (high comp engine).
I reckon possibly two problems here. A. Running rich. B. Something happened as I drove it for the test and it's coincidence that the the tester drove it immediately afterwards.
Anyway, long post but trying to give as much info as possible.
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