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Starter and grinding noise, motor starts and runs fine

H

hirvelam

New member
I have been reading about others that have this same issue with a grinding noise when engaging the starter, however my symptoms are different.

The boat is a 2008 Chap with a Mercruiser 5.0 EFI Serial number 1AO78945. The boat was purchased new to me last year and only has 75 hours on it. I had a service done this winter where I had plugs replaced, had the service center run diagnostics since the boat was new to me and it passed all the tests (i.e. Compression).

The boat ran 2 weeks ago on the water and ran great. No starting issues of any kind. I dropped the boat in the water yesterday and when I turned the key it made the grinding noise when I engaged the key, but quickly turned over and ran great. We took the boat out and anchored up at the sandbar for a couple of hours and the boat just sat. When I went to start back up, the grinding noise continued and the starter had to cycle a little longer but it started and ran great. We pulled the kids back to dock on tubes and the motor ran great (outside of the starter issue). Since it cycled so hard to start, i didn't shut it down until the boat was out of the water.

It sounded to me like the starter wasn't fully engaging the flywheel and that maybe the teeth of the starter were on engaging a little bit and slowly getting sheered off. Each time I tried to start after the initial time, the grinding was worse and the starter had to cycle longer, no more than 5 seconds.

I was under the impression that the starter just needed to be replaced, but based on reading the posts from others, it sounds like it is much more.

After reading about hydrolock, I went out and pulled all the plugs and they were all dry, except the front starboard side which had a tiny bit of oil an oily substance on the end of the plug threads, but not wet by any means.

Any thoughts of what I should do next? I am thinking about replacing the starter but I am asking myself what caused this issue in the first place? The starter appears original and I am guessing it could have just worn out and the plunger isn't fully engaging. But i don't want to burn up a new starter if that's not the issue. I also have been reading about all the issues guys are having when replacing a starter (shims, no Shims, how much to shim???) UGH...
 
Probably the stater bolts are loose or incorrect bolts are used which allows the starter to twist and gears don't engage right. Check that they are tight,and not bent.

You risk breaking a bolt off in there which is a PITA to fix and or ruining the flywheel ring gear.

Also, it is possible if the starter was replaced with permanant magnet starter the wrong bolts were used. Merc starters are painted black like engine.
 
Dieter

Thanks for the response. I spoke to my mechanic and he eluded to the possibility off a loose bolt. My concern is the bolt loosening in the first place, and if the hole is getting stripped out. The starter that is installed is painted black like the block and the rest of the parts and has the SAE 1171 sticker on it as I have seen on the OEM replacements. It does not appear any of the bolts have ever seen a socket or wrench on them as there is no wear. I will dive in this evening and see if I can tell if the starter bolts are loose. If it is original and 12 years old, it might just be worth replacing it and not worrying about it again or eliminating the risk of it going bad.

Do you think it is worth pulling it to inspect the teeth on the fly wheel while I am doing this?
 
FYI..... starter motor mounting bolts must be correct for the starter motor nose housing.
Not all nose housings are the same today.
A wrong length bolt may bottom out before fully clamping the nose housing to the cylinder block.
These bolts not only secure the starter motor to the cylinder block, they also align the starter motor.
 
hirvelam said:
Dieter

Thanks for the response. I spoke to my mechanic and he eluded to the possibility off a loose bolt. My concern is the bolt loosening in the first place, and if the hole is getting stripped out. The starter that is installed is painted black like the block and the rest of the parts and has the SAE 1171 sticker on it as I have seen on the OEM replacements. It does not appear any of the bolts have ever seen a socket or wrench on them as there is no wear. I will dive in this evening and see if I can tell if the starter bolts are loose. If it is original and 12 years old, it might just be worth replacing it and not worrying about it again or eliminating the risk of it going bad.

Do you think it is worth pulling it to inspect the teeth on the fly wheel while I am doing this?
Click to expand...
Depends on how loose the starter is. If it hasn’t been moving too much I’d say no as it is an MF to get the starter in down there. Start by tighten them up.

Same thing happened to my buddy’s boat took one bolt out at a time to location them so they wouldn’t loosen up again. Didn’t have to drop whole starter.
 
Dieter, You Nailed it! I went out last night and put a socket on the starter and both bolts were loose. I tightened them and tested it and it took off no problem. No noise. To be safe I pulled the bolts one at a time to inspect them. (Didn't want to lose alignment as you eluded to). I ordered to new OEM bolts and will replace them just to be extra safe. I still asked what caused them to loosen in the first place. I guess it is possible from the heating and cooling process of the block and weather to cause them to eventually loosen? I also had a post on another forum where a guy found out that the shop he used was loosening bolts to get more work. I don't think that happened, but its possible since I have only owned the boat for year.

Thanks for the help.
 
Where I saw this on my friends boat the starter had been replaced 6 or 8 years ago. There's not much room to work and you're hanging upside down. There's a lot of torque on just two bolts. One of the bolts on his was noticeably bent I couldn't find a replacement on short notice in BFE where we boat so just used loctite.

just keep an eye on it easy enough to put a wrench on it a couple times per year.
 
Its interesting you mention the bolt being bent. The one I pulled out had a slight bend to it also. SO much so that when it was taking it out and putting it back in, the bolt would bind when I caught the bend just right. I would have to but the socket on it to get it moving again (very little force) then I could go back to finger tightening it. I understand that there is a significant amount of torque on the bolts from the movement of the start engaging the flywheel. But those are some significant bolts. After seeing the bend I ordered the new ones and will install them in a few days. For 28.00 for both bolts it was worth the peace of mind. I know know to keep a socket that size on my boat just for that reason and will check it whenever I do my deep cleanings (2-3 times per year). Thanks for the help.
 
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