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2002 Mercruiser 6.2L mpi that sat for 2 years

Discussion in 'Engines' started by CHRIS RANKIN, Aug 6, 2022.

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  1. CHRIS RANKIN

    CHRIS RANKIN New Member

    Joined:
    Aug 6, 2022
    Messages:
    1
    Location:
    KY
    My boat sat for a couple of years during Covid. I changed the oil and primed the engine without starting it. I pulled the plugs and fogged the cylinders with oil. Later, I proceeded to try and turn the engine over by hand at the crank pulley. I would apply approximately 50lbs of force on a 18" torque wrench and then ease off and I continued to do this for 4-5 times until the engine broke free. When the engine did break free, I heard a "ping". I would assume this noise came from a piston ring, although I don't know that for sure. I would like to hear your thoughts on the matter. The engine turns over by hand freely without any unusual noises. Should I be concerned about starting the engine?
  2. Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    12,649
    Location:
    Satsuma, FL
    That ping or tink could have come from anything including your pull bar.
    The real test it to pull it over past 2 revs.
    Put a pipe on a pull bar. 18" is hard to pull on.
    Tight on room, put a pipe on a 1/2" ratchet.
    Facing the motor front, turn Clockwise. Counter C may loosen the crank bolt.
    If it does not bind up during those 2 turns, crank it up.

    Awaiting your update. :)
  3. mapism

    mapism Senior Member

    Joined:
    Aug 9, 2008
    Messages:
    2,111
    Location:
    Sardinia
    CR already said it all, really.

    But just for your reference, I use a 60cm (24" or so) ratchet wrench for turning my 15 liters diesel engines, and while I never bothered checking with a dynamometer, by and large I would say that somewhere between 30 to 40 lbs of force is enough to turn them.
    So, 50lbs for a 6.2L petrol engine sounds a tad high to me, also considering the shorter lever. Anyway, if once moved it spins regularly, as long as you can complete two full turns (to be sure that all the valves are cycled), you should be good to go.

    If you should leave the engine sitting for a long period again, you might consider turning it manually now and then, to avoid leaving the same valves open. A 180 degrees turn is enough to be sure to close any previously open valves.
    Another thing I like to do when turning on engines which sat for some time is to crank them for some seconds while keeping the stop button pressed, in order to circulate oil before actually firing them up.
    The feasibility of this depends on the wiring, though: I've seen several petrol engine powered boats where for shutting the engine down you must turn the same ignition key CCW, so in this case you can't crank the engine and keep the stop pressed at the same time...