Seized motor

[st419]

I have a 97 XP with the 787 carbed, starter hits but does not turn over I took the head off and the pistons flutter a little but does not make a full rotation seems seized but why do pistons move? Please help

 

[mikidymac]

Pull the pump firts as it might not be the engine. If pump is not locked then..
If pistons move then its the crank, balancer shaft or rotary valve athat are bad.

 

[rkkoeb]

I had the gear on my crank for the rotary valve moved and locked up the motor and did damage