Have you set the valve timing, that is with a dial gauge, I could not get mine as per the manual but I have them as close as I can, by leaving the the tappet adjustment closer on one and maybe wider on another, this will make the tappets rattle but if its for racing this should not matter, I have mine set for road use to keep the engine noise to a minimum, on the carb side of things if the left side spits on tick over or just open start the engine and with your finger push forward on the throttle slide to see if it cures it, if so then the throttle slide is worn, please take these as hints as I am not an engineer and can only tell you my own experences over the 30 years that I have owned the Interceptors.
Do I take it that the performance is also down? their is a couple of things to check that I can think of: Check that you have the correct camshafts, I think that they only fitted one type to the MK11 and three diffirant ones to the MK1/1a so not sure if any are interchangable, on one of my MK1 engines which was under performing (would go well till you shut the throttle and then opened up again, then it would not have any power) this was found to be due to having to Exh cams fitted sometime before I got it, and I have read this somewhere that it was for racing where the engine spent most of its time on full throttle, not very good for road use, the other thing is quite silly really and that is have you changed the silencers over to see if one is straight through? their have been a couple of differant silencers on the market some quiteter that others. Tom.
Hi Hogan, Yes I think maybe we have a common interest, I have had the MK1 since 1978 and run a Consellation before that, what sort of running problems are you having with your MK11? only had my MK11 for just over a year now and have had one or two problems myself so its good idea to share them with others. Tom.