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57L Tune Up

njyankee

New member
"I recently bought a boat with

"I recently bought a boat with twin 1999 5.7 L Merc Inbds. The guy before me didn't use the boat much and I think the engines may be neglected. I want to go over them and do a complete tune-up, but don't really know what that entails. I'm pretty mechanical and have some experience working on gas engines, but don't know what list of things I should address for a "full tune-up." Any advice? Thanks."
 
"Well,..... A Basic Tune Up is

"Well,..... A Basic Tune Up is Plugs, Cap, Rotor, Fuel Filters,+ an Oil Change.......

A Full Tune Up in My Book includes Checking Everything that CAN be Checked.....
And,...
I think that a Factory Shop Manual is the 1st Necessary Tool to get That Done.............."
 
"If it was neglected, I would

"If it was neglected, I would also do a compression test and if possible, a cylinder leakdown test. Go over it with a fine toothed comb and don't skip anything that bothers you. Any corrosion you see, fix it, especially if it's on the wiring. Make sure everything is tight, connections are sound and there are no leaks. Once the new cap and rotor are on it, check/verify the timing."
 
"Thanks guys. They do seem to

"Thanks guys. They do seem to run well, it's just my piece of mind of putting my hands on them and knowing the maintenance is reasonably up to date. I think I'll start with the stuff Bondo mentioned and then do the compression test. There really isn't much corrosion (if any at all), but I will definitely be going over that when I replace the gauges and sending units.
Thanks"
 
"Might want to Check the Belts

"Might want to Check the Belts, Hoses,+ the Impellers while you're at it........
wink.gif
"
 
"The corrosion you can't s

"The corrosion you can't see is what will strand you. remove the nut that holds the grounds onto the blocks and clean the ring terminals, nuts and studs. Do the same on each motor and remove the starters so the Bendix can be lubed, then clean the mounting surface of the block and starter on each. Neglecting this will strand you at some point, especially if they sat for any length of time. Also, prop the motor boxes open slightly when you store the boat so the air can circulate and any condensation will evaporate faster."
 
Thanks for the info guys. I wi

Thanks for the info guys. I will definitely incorporate the guidance and let you know how it goes. Thanks.
 
"I replaced my 5.0 with 5.7 ,

"I replaced my 5.0 with 5.7 , 1995, Thunderbolt IV igniton. Intake valves were tuliped on 5.o. I am concerned about Pre Ignition. What should timing advance be at 4000 Rpm. It is about 39 degrees. OK? What should it be.}}"
 
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