Killed another starter? Or is something else amiss? confused.....

OK, last year I replaced what looked like the OEM starter on my 96 5.7 merc. symptom was the starter motor would spin but not engage the flywheel. I figured the solenoid so I ordered a new "offbrand" starter and it worked. Last year when trying to winterize the engine wouldn't start. Cranked and cranked and then starter did same thing as last one, motor would spin but not engage the flywheel. Figured I burned out the new starter and winterized and forgot it. Problem is still there now that the boat is unwrapped. The odd part is that I have both starters and when testing them out of the boat they seem to work. Applying 12 volts to the solenoid throws out the pinion gear, jumpering the leads and the gear comes out and the motor spins. The starter was still tight when I removed it so it did not move away from the flywheel. Checked for broken teeth on the flywheel and starter and nothing found. What am I missing here? I have no way of putting a load on the starter to see if the gear spinning on the starter motor shaft which is the only other idea I have.......

thought of pop starting it but I cant push the boat fast enough

Re: Killed another starter? Or is something else amiss? confused.....

Has the starter been shimmed properly? Were there shims on the old starter when you took it out?

Re: Killed another starter? Or is something else amiss? confused.....

No shims on the old starter but needed them on new starter. Tried it without any first and it bound up. Put 2 shims in and it didn't work. 1 shim did the trick and it was still there when I took this one out.

Re: Killed another starter? Or is something else amiss? confused.....

Since the new starter worked when you installed it, I don't think you have a shim problem. Problem sounds like the starter bendix (starter drive) has gone south. The clutch in it is not engaging. First question, are sure it's a "new" starter and not a rebuilt starter? Seems like anything rebuilt takes 2 or 3 times to get a good one. The new definition of rebuilt is only replace the bare minimum to make it work and hope for the best. That and then there's all the parts from China that have so little quality control.

Re: Killed another starter? Or is something else amiss? confused.....

OK here are the 2 starters, old and new. Can you explain better what the starter bendix is? Can it be tested? So the fact that the gear is coming out and spinning doesn't mean the clutch it working? Lot of questions but I want to make sure I understand correctly. Thanks

Re: Killed another starter? Or is something else amiss? confused.....

There's a place on ebay that sells marine coated starters for GM V8s for something like $80 shipped, they are the updated permanent magnet gear reduction type and it has been extremely reliable for me. I bought 2 so I can keep an extra on board the boat, I thought since they were so cheap I'd need a spare but the first one I bought has been performing flawlessly.

I highly recommend this starter, don't worry that it says 502ci, it fits all mercruiser except 3.0 liter.
Marine Coated Starter Mercruiser 500 8 2 502CI 8CYL 1999 2000 18 5913 50 12121A2 | eBay

Re: Killed another starter? Or is something else amiss? confused.....

Thanks, I got my replacement off of crapbay but I want to make sure my issue is actually the starter.

Re: Killed another starter? Or is something else amiss? confused.....

subysti said:

OK here are the 2 starters, old and new. Can you explain better what the starter bendix is? Can it be tested? So the fact that the gear is coming out and spinning doesn't mean the clutch it working? Lot of questions but I want to make sure I understand correctly. ThanksView attachment 193617

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the bendix is the gear that pops out when starting (its the piece the gear is attached to that rides on the shaft and normally can not be disassembled). the solinoid on the side uses a lever to push the bendix into the flywheel. The jolt of the bendix engaging the flywheel is reduced by the clutch built into the bendix. Once the clutch burns out then the bendix will engage the flywheel and spin on the shaft. There is normally a warning where the motor will crank but sounds like its speeding up and slowing down while cranking before the clutch dies. Another problem could be that the engine likes to stop in the same spot so the starter is constantly hitting the flywheel on the same tooth and is tested by turning the motor over with a wrench 1/8th of a turn then trying to start the motor or by looking at the teeth which you have already done. Bendix can be replaced on its own if its a name brand starter and is easy to replace (its a pain to work out the bendix part number on the off brands).

Re: Killed another starter? Or is something else amiss? confused.....

So then if I understand correctly, the clutch holds the bendix gear to the shaft. So the gear will engage flywheel but just spin on the starter motor shaft? Will cranking and cranking burn this out? Where could I get these parts?

Re: Killed another starter? Or is something else amiss? confused.....

subysti said:

So then if I understand correctly, the clutch holds the bendix gear to the shaft. So the gear will engage flywheel but just spin on the starter motor shaft? Will cranking and cranking burn this out? Where could I get these parts?

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cranking and cranking can burn them out but its not normally not the first part of the starter to fail (edit: on a standard non gear reduced starter its not the first part to fail). A starter rebuild shop will be the best bet. Ask for a quote on the part then decied if its worth rebuilding verses replacement.

Re: Killed another starter? Or is something else amiss? confused.....

subysti said:

So then if I understand correctly, the clutch holds the bendix gear to the shaft. So the gear will engage flywheel but just spin on the starter motor shaft? ?

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The bendix has a one way clutch or over riding clutch inside itself which allows the gear to spin freely on the main shaft in one direction and catch or hold in the other direction. This allows the spinning starter to engage the flywheel and spin the engine over to start. A sometimes simple way to test the bendix when off the engine is to grab hold of the bendix gear while assembled in the starter and turn it by hand in one direction then back the opposite direction. Try this at several different points and it should spin freely one way and catch in the opposite direction. When they are bad you can sometimes turn it freely in both directions. Hope I explained that clearly for you to understand.

Re: Killed another starter? Or is something else amiss? confused.....

(I reread your post and this advice was redundant)