Tractor Repair: case 2390 timing, crankshaft pulley, engine valve

Question
where are the timing marks located?the tractor smokes like a freight train.

Answer
There are marks on the crankshaft pulley and there is a pointer on the front timing cover of the engine.  There are also marks on the injection pump.  Remove the large plug above the area where the injection pump mounts to the engine to see the pump timing marks.  Turn the engine in the normal direction of rotation until the pump marks line up.  The appropriate mark on the pulley must line up with the pointer.  The correct timing is listed on the specification decal on one of the engine valve covers.  If the smoke is black, check your air intake, air filters, and turbo.