2000 johnson 50

[chris]

had problems with motor running took to machanic he said sealing rings were bad where are they located

[boats.net]

He may be talking about the piston rings, number 2 in this link Johnson Outboard Parts 2000 J50ELSSA Elec. Start, Tiller, 15 IN. shaft 2000 CRANKSHAFT & PISTON Diagram
If he found low compression the piston rings, pistons or cylinders could be worn.

[chris]

machanic said piston creates a vacume witch pulls fuel from carb if sealing ring is not working it pulls vacume between cylender is their any truth to this

[boats.net]

That engine doesn't have seal rings on crankshaft like some models, if leaking between cylinders would need to check block, main bearings and crankshaft for wear.