72 Merc 50hp 500 Thunderbolt

"I am brand new with outboards

"I am brand new with outboards and have come into a 1972 Merc 50hp 500 Thunderbolt (Ser. No. 3359071.)

The controls were not connected but I think I connected them correctly, hoping to put the motor into neutral to see if I could tell if the motor is seized.

I can turn the motor by hand 3/4's of a revolution and there is a slight 'poof' sound as though a piston may be releasing pressure.

Can a seized motor be turned - at all - by hand or do I need to find a battery to give it more oomph? I won't be doing that - no guts.

I am going to have a pro do whatever needs doing - I am just curious if the thing is seized. Didn't pay a dime for it so no need to be gentle !!!

Thx all,
Mike in Washington"

"remove the plugs, put some oi

"remove the plugs, put some oil in the cyl's and spin the motor by hand. the controls do not have to be hooked up to start the motor. if all goes well you can spin it with the starter with the controls or by jumping the solinoid or pull starter. before starting the carbs should be cleaned and check for spark on each cyl. lack of fuel to any cyl means no lube"

"I have a 1973 Mercury,50 HP,

"I have a 1973 Mercury,50 HP, 500 Thunderbolt motor. I just brougt it and the boat had not been in the water for 3 years and was only cranked twice a year. I poured out the old gas and on the 4th tank it was running wide open and it shut down like it had no gas, so I choaked it and it picked up and kept shutting down. I put new spark plugs and not chane. Sometime it would pick up and run wide open for 2 or 3 minutes and shut down again
."