Engine misfiring on start up

Now turned my attention to the carburettors.
Removed both carburettors, cleaned the new inlet manifold 0 rings and used a standard washer on the 4 mounting bolts ( part number 550054) with the intention of exerting more pressure against the new seals, and hopefully reduce or eliminate any gap. The S. U.instructions advise setting the jets level with the bridge and then enriching two full turns. I went for broke and gave each carb five full turns.With full choke, the engine started after a couple of turns.
The carbs are still pulling air, ( still waiting for Hylomar), there is a bad leak on the exhaust manifold, the engine is running, I'm happy with that.
Thanks everyone for your help, it's really appreciated