Starter is spinning cleanly but not engaging the flywheel?

2007 MERCURY MARINER
200,000 MILES • 2.3L • 4 CYL • 4WD • AUTOMATIC
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THEMANTIS
I have a 2007 Mercury Mariner with the 2.3L engine. it won't start and you hear the starter spinning cleanly with no grinding. I swapped starters, same issue. We bench tested the old starter and it was working. Tested relays/fuses. Bypassed S control wire. Still spins with no engagement. No flywheel damage. Tested battery and it was good. It seems that the starter isn't getting the needed power to kick out the bindex to engage the flywheel and start the engine.
Feb 27, 2026 at 11:17 AM
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STRAILER
  • ✓ASE Certified Mechanic
  • 54,494 POSTS
  • ASE Certified Mechanic
If the battery and is and there is no flex plate damage the starter is the issue. Did you get the starter from ROCKAUTO? I have seen cheap replacements have this problem. Also, check the ground wire from the battery to the engine block and to the car chassis to make sure the connections are good. I would turn the headlights on to see if they go dim when the engine is cranked, this is a sign the voltage is dropping to much. Please upload a short video in your response of the problem, so I can see what's going on. Ken
Feb 28, 2026 at 9:54 AM
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