3.0 mercruiser starting problems/grinding noise

I bought a 1999 bayliner w/ an 3.0 mercruiser,it had a broken starter bolt, had that fixed and replaced starter along with rear starter bracket to avoid anymore broken bolts because of torques from starter. The first few times I started it on the tralier after this it starter fine,ran it for a while ,then it in the water ran for a little bit ,then died (bad gas) but when trying to start it sounded like starter grinding on flywheel ,after going through this process twice and even thinking the starter was bad and shimming the starter, got to the point where i inspected the gears on teh starter and teeth on the flywheel, everything looked fine but now wont even turn over goes right to grinding aweful. Even tried to manualy turn engine to get to different teeth on flywheel but same thing. I did notice when turning the engine that there was a hard spot when turning so i took out all spark plugs and still has ahard spot when turning.Can someone tell me if there is something internally going on in the engine or something like a bad crankshaft bearing causing the bind.I have read a few post about similar noises and all the other mention a new starter or shims, But I have done both , a boat mec. looked at it and said its inside engine but before i replace it I want to be positive its not and easy fix,

Re: 3.0 mercruiser starting problems

Re: 3.0 mercruiser starting problems

Well, could be a lot of things.

1st thing to do is make sure you have a marine starter.
2nd thing is to remove any shims from the starter -- you don't need them and they will cause excessive wear...

The grinding noise you hear is the starter gear (called the starter bendix) not properly engaging with the flywheel.

This can be caused by a number of things.

Like I said, make sure you have a marine starter.
Make sure you put all 3 bolts in, then tighten the one on the back first -- this will make sure it lines up right.
then tighten the front two bolts...

Check your battery -- these starters use an electric solenoid to push the bendix out to grab the flywheel teeth -- not enough voltage = not enough push = will not grab...
Check the secondary solenoid -- follow the big wire from the starter. It should go to a round black thing with two big wires (red) and one small one.... This is the secondary solenoid. Check voltage accross it when a help turns the key to start -- any voltage across it = bad.

remove the starter and check the teeth on the flywheel and on the starter. The flywheel teeth should not be worn on the front side.

return the starter for an exchange -- it could be defective........

To answer your question, there should be four hard spots (in any given 2 rev's of the crankshaft)... The hard spots are the compression stroke of a particular cylinder.....

Hope this helps

Re: 3.0 mercruiser starting problems

Re: 3.0 mercruiser starting problems

Whoops, sorry, just re-read your post...
Compression hard spots should go away with spark plugs removed.......

Re: 3.0 mercruiser starting problems

Re: 3.0 mercruiser starting problems

I do have a marine starter ,order a new one online and bought a brand new battery. I took the shims out,I even tried a different starter from a friends boat with the same engine and it did the same thing. As I watch the engine turn or try to when i turn the key it only turns a 1.4 of a turn ,it will not turn a full turn at all.

Re: 3.0 mercruiser starting problems

Re: 3.0 mercruiser starting problems

shawn89 said:

I do have a marine starter ,order a new one online and bought a brand new battery. I took the shims out,I even tried a different starter from a friends boat with the same engine and it did the same thing. As I watch the engine turn or try to when i turn the key it only turns a 1.4 of a turn ,it will not turn a full turn at all.

Click to expand...

It may be time to pull the outdrive off (not that difficult) and see if this frees your engine up. Even in neutral everything in your outdrive is turning down to the final gears....

Happy boating!

Re: 3.0 mercruiser starting problems

Re: 3.0 mercruiser starting problems

So it may be in the outdrive and not the motor itself?

Re: 3.0 mercruiser starting problems

Re: 3.0 mercruiser starting problems

shawn89 said:

So it may be in the outdrive and not the motor itself?

Click to expand...

You will not be the first to find this...!

And it will isolate that possibility, and maybe save your new starter.

Happy boating!

Re: 3.0 mercruiser starting problems

Re: 3.0 mercruiser starting problems

what is the easiest way to pull the out drive?

Re: 3.0 mercruiser starting problems

Re: 3.0 mercruiser starting problems

shift into fwd, remove the rams. remove 6 mounting nuts, pull straight back and off.

Re: 3.0 mercruiser starting problems/grinding noise

Depeding on the water its been operated on and how long it's been since it was last pulled, you may find that a bit of effort is required to pull it off.
I'd suggest removing the little rubber hose on the back side of it (if yours has this -- its for the speedometer -- its connected to the top of the lower unit -- you'll have to tilt the drive up to see it -- just squeeze the tabs and it pulls right off.)
Then just remove the 6 nuts (should be 5/8") and pull it straight out -- be ready, it's a little bit heavy.........

shawn89 said:

I bought a 1999 bayliner w/ an 3.0 mercruiser,it had a broken starter bolt, had that fixed and replaced starter along with rear starter bracket to avoid anymore broken bolts because of torques from starter. The first few times I started it on the tralier after this it starter fine,ran it for a while ,then it in the water ran for a little bit ,then died (bad gas) but when trying to start it sounded like starter grinding on flywheel ,after going through this process twice and even thinking the starter was bad and shimming the starter, got to the point where i inspected the gears on teh starter and teeth on the flywheel, everything looked fine but now wont even turn over goes right to grinding aweful. Even tried to manualy turn engine to get to different teeth on flywheel but same thing. I did notice when turning the engine that there was a hard spot when turning so i took out all spark plugs and still has ahard spot when turning.Can someone tell me if there is something internally going on in the engine or something like a bad crankshaft bearing causing the bind.I have read a few post about similar noises and all the other mention a new starter or shims, But I have done both , a boat mec. looked at it and said its inside engine but before i replace it I want to be positive its not and easy fix,

Click to expand...

2 important lessons (hard lessons). Pull your starter and make sure it has proper number of teeth. I ordered a “replacement” that was supposed to fit, which it did bolt up exactly as the original, and I discovered that not only did the new starter have 11 teeth (instead of 9 like the original) the new starter shaft was also approximately 3/16” shorter than the original. After getting the correct one the starter works as designed.

MOD EDIT: A third important lesson. Please review the forum rule about posting to old threads. this one is 12 years old.