Mercruiser 502 (7.4l) turning over slowly, won't start.

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Robert Marine

Cadet
Joined
May 22, 2022
Messages
15
1993 bowrider with a mercruiser 502 EFI engine. Was attempting to jump start it and it would turn over slowly but not start and then eventually wouldn't turn over at all.
Pulled the old starter and it was non-working. Put in a new starter and and new batteris. Now the engine turns over but very slowly and sounds sluggish as before.
Any ideas?
 
alldodge

alldodge

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Mar 8, 2009
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42,054
What is the history of the boat?
Is it new to you, was it running fine prior?
 
Bondo

Bondo

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Robert Marine said:
1993 bowrider with a mercruiser 502 EFI engine. Was attempting to jump start it and it would turn over slowly but not start and then eventually wouldn't turn over at all.
Pulled the old starter and it was non-working. Put in a new starter and and new batteris. Now the engine turns over but very slowly and sounds sluggish as before.
Any ideas?
Click to expand...
Ayuh,..... Welcome Aboard,..... Did you clean to shiny metal, both ends of both battery cables,..??
 
D

dubs283

Vice Admiral
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Jul 27, 2005
Messages
5,322
If it's a sterndrive I'd pull the drive and test the starting again

If it's an inboard/v drive the issue could be within the transmission, engine mechanical or still an issue with the starter/batteries
 
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dubs283

Vice Admiral
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Jul 27, 2005
Messages
5,322
Robert Marine said:
Uh oh. Oil is thick forest green. Looks like someone put gear oil in engine at last service.
Click to expand...
This is the first time you've checked the oil level/quality? As in you attempted to start the engine for the first time in six months without checking fluid levels prior? And someone besides you did the last oil change?
 
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