this on a rebuild i believe it the oil slink.. with out it turns fineHydro-locked with fuel maybe?
Pull the plug. Crank over the engine. See if fuel dumps out the plug hole.
engine on bench no internal parts broken. if i reassemble with out oil slinger turns fine.BEfore we go any further
What condition is the engine in right now
Together & in the mower or apart and on your bench ?
Did it rotate a full turn with the sump off ?
31c707 0230E1 03 430zeNeed engine info, model, type, code??????????