115 hp johnson wont turn

I have a 115 hp 1991 motor. Pu

I have a 115 hp 1991 motor. Put 2 new pistons in the top. everything turns fine when on the bench.when i put it all toghether it turn good. when i put the power head on the boat then try to turn it over it turn ok for a few seconds the kinda locks up it takes all of what i have to turn the fly wheel.later when i try it again it does the same thing. pull power head again and rechecked. everything seemed ok. put it all back toghether. same problem. Talk to someone they said they seen the fly wheel jam on the stator.will try pulling this tonite and check.any oppions out there on were i should go next.

thanks

"i wouold ck the lower unit,to

"i wouold ck the lower unit,to make sure u have no problems there,and u should be installing a new water pum kit anyway.be sure u find the problem,before u try to start it,or u will def do some serious damage,somewhere.!"

"thanks jw
I did pull lower

"thanks jw
I did pull lower unit off, already put the pump kit in. that turns fine and works., pistons turn good when power head is on bench. seems like when we put the fly wheel on and try to start it, it turns ok for a few seconds starter has a hard time turning it after that then when i try it the next day it turns ok for the firts few seconds with out even starting then it turns hard.."

Next time you try this pull th

Next time you try this pull the plugs & see if it turns over. I wonder if you have water leaking into one or more of the cylinders.