1969 Evinrude 4906B 4hp assembly

[74bayliner]

Hi, I am reassembling this little motor and im watching a few clips on the internet and see that when people spin their crankshaft it easily spins with the pistons in and the spark plug holes open.
When i put the pistons in mine, for some reason they do not turn at all... i cannot spin them by hand and barely if i put the flywheel nut and use a socket to turn it.


Why is this? Am i doing something wrong?
I checked the piston measurements and they are smaller than the cylinders even with rings on shouldnt they be doing what everyone elses are doing on the youtube videos and spinning by hand (not freely obviously but be able to spin the crank by hand.

 

[F_R]

Yep, it should spin easily.
Rings oversize? Pistons oversize or out of round? Connecting rod caps on wrong rods or turned end-for-end?
Crankshaft bearings tight? Crankcase sealer in the bearings?
Failure to first insert tapered dowel pins before tightening crankcase screws?

 

[74bayliner]

Thanks @F&R i will check all of these. Im having lasik surgery in 3 hours but hopefully i can get out there after i wake up :joyous: