Outboard locked.

[bigman1]

I have year 2000 40hp mariner manual start outboard, pull start won't turn over, took out spark plugs turns over fine,put plugs back in won't turn over. Can anyone help. Thanks.

 

[flyingscott]

wrong plugs?

 

[kimcrwbr1]

Did you have your wheaties? On the older engines that first pull can be a bear especially if it is a two cylinder engine.

 

[Canufixit]

Was there fluid in the cylinders (i.e Fuel, water, etc.) Be sure and check.
With the plugs out you can easily spin the flywheel - did you place a stick in each plug hole and verify the pistons are ll moving back and forth??
Any chance that when you prime it /or the fual pump is flooding the carbs into the pistons/crankcase?
Exhaust blocked?