Restarting a Mercruiser That's Been Sitting For Years

[Beldar364]

1999 Bayliner 2050LS (CX) USHD11CXI899
With a Mercruiser I/O 5.0

Boat has been sitting idle for 5 years (supposedly winterized before sitting)

I have an automotive background, but limited boat background. Want to get the engine ready to use but shop has a 2 month backlog so I decided to do this myself. Not sure what all needs to be done.

I would venture a guess that I need to:

Change oil & filter
Replace drive belt
Replace hoses
Clean carb
Soak each piston with Marvels Mystery Oil
New spark plugs
New spark plug wires
Any other suggestions?


Have no clue what to do about foot or tilt/drive unit.


Any guides on forum or online that are useful? I did brief search to no avail.

 

[Bt Doctur]

Change oil & filter before you even start the motor, could have a lot of condensation in the pan
Replace drive belt maybe, but a good idea
Replace hoses not really ,unless there rotted
Clean carb see how it runs
Soak each piston with Marvels Mystery Oil definitely, turkey baster works for that
New spark plugs Yep
New spark plug wires maybe, see if there is and arcing
Any other suggestions? Drain the tank and put new fuel in, replace the fuel sep filter. I would pre-oil the motor thru the dist hole while turning the motor over a few times.
post some pics of what you got.

 

[Scott Danforth]

pull the lower unit, replace the impeller.

 

[Bayou Dave]

Make sure you have a hose and muffs when you attempt to start it.

 

[bruceb58]

I would pull the distributor and buy the tool that attaches to your drill to operate the oil pump until oil pressure is fully up. That is what I did to an engine that was laid up that long. Also, forget using the fuel that is already in the tank. Use an external tank.

Hand rotate the engine a few times with spark plugs out before using the starter.

 

[DALOW]

I have a 5.0 Mercruiser that was sitting for 5 years. I rebuilt the carb because it was grody inside, new point and condenser. I have since replace it with the pertronix. I added gasoline to what was there and it didn't seem to hurt it. New fuel / water separator...
Never thought to use the mystery oil... might be good... who knows its a mystery...
Started right up and ran like a champ 21 years ago. It was 20 years old when I got it and I've been using it every summer for 21 years. Same fuel pump, alternator, starter motor, Hoses are still good after 40 years. Hard to believe.

 

[philipp10]

my 2 bits:

Change oil & filter: Just check the oil, it might be new and no, there won't be condensation in there as there has been no air movement in storage.
Replace drive belt: Just inspect it
Replace hoses: Inspect
Clean carb: See if it will start first, might be fine if they had ran it dry in winterization, will need to pour fuel down the carb?
Soak each piston with Marvels Mystery Oil: YES
New spark plugs: Why? They don't go bad from sitting
New spark plug wires: Why? They don't go bad from sitting
Any other suggestions?

As far as taking out the dist and running the oil pump to bring up pressure, no need to, just crank the motor over by hand with a wrench. Oil pumps almost never fail, the pressure will come up whether it has sat a week or a couple years.

 

[bruceb58]

Oil pumps almost never fail, the pressure will come up whether it has sat a week or a couple years.

The reason I mention this is not because of oil pumps failing. It's because of lack of lubrication from sitting so long. Also, if the oil pump has drained and lost its prime, this allows the pump to get up to full pressure faster at the initial start.

 

[poconojoe]

I'm thinking, inspection and or clean the old spark plugs. After all that marvel mystery oil is burned off from initial startup and it's running good, then change the plugs. This way, the new plugs don't get fouled up.

 

[Beldar364]

The fuel tank is empty & looks clean. I had to replace the floor in the boat so I got a good look at it. If it get's less than 100 degrees this weekend I plan on starting to work on it.

Thanks for the help.

 

[fishrdan]

Bellows have a 5 years service life, and the boat has been laid up for 5 years, so....... You won't need to replace them before firing up the engine, but they need to be inspected closely for splits, cracking and/or dry rot before dunking the boat into the lake. They may be OK to run the boat for a while , but I'd replace them.

 

[philipp10]

I'm thinking, inspection and or clean the old spark plugs. After all that marvel mystery oil is burned off from initial startup and it's running good, then change the plugs. This way, the new plugs don't get fouled up.

If the motor is running well, no reason to change the plugs. A good running motor will burn off that little bit of oil in no time. Its a waste of money to change plugs, they almost never wear out.

 

[Beldar364]

Thanks again for all the help. Finally got it out on the water this weekend. No engine problems, the only issue we had was with tilt & trim. I couldn't get it to move from the switch but could move it with a jumper wire on the solenoid. Hopefully get to look at that this week.