Hi i have just obtained a Lister LR1 3.5 hp 750 rpm  but cant get the engine to run  the engine has good compression as i have replaced rings and ring end gap is within limits
set bump clearance to 25 thou  checked and reset valve clearance to 6 thou inlet 8 thou exhaust as per workshop manual  Also bled the fuel system  the fuel injector has also been serviced. the fuel pump has not been touched as the engine was running a few years ago i can hear injector working when turning  the engine over,   When i tried to start the engine  place the excess fuel lever in correct position downwards and decompression lever towards flywheel end and turn engine over briskly  pull decompression lever  back, the engine fires once and some times kicks back, also exhaust smoke comes out of inlet manifold i think may be the timing is out would be greatfull for any advise offered PS when i removed the flywheel  the key was sheread off
both keyways were undamaged replaced with new key could this be causing  the problem
Many thanks
Steve c