Mercruiser 3.0 squeal keeping engine from starting

[1997BR176]

Did you try cranking with the plugs in, all accessory belts off? Water pump siezing could be a thing...

Yes, you may be able to notice the belt is just there not moving.

I was able to keep it running now after adding some STP oil treatment but the squeal/noise is still there. but now it doesn’t cut out on it own.

 

[1997BR176]

I would turn it over by hand not with the starter so you can fell if something is hanging up.

I’m not sure how to do this because the engine mount is in the way of the crankshaft pulley. Please let me know if there is another way to do this. Thank you.

 

[1997BR176]

First start after adding STP Oil Treatment. Noise still there.

 

[1997BR176]

Last vid for tonight. Thanks for all your input.

 

[Alumarine]

I’m not sure how to do this because the engine mount is in the way of the crankshaft pulley. Please let me know if there is another way to do this. Thank you.

You can put a socket on the alternator nut and rotate the motor.
You will probably have to put tension on the belt with your hand to stop it from slipping.

 

[ltklein]

Sounds like it's half speed relative to the cranking. I'm thinking distributor bushings...

Mechanics stethoscope is like $5. Can touch it to the base and crank, or just pull the distributor assuming you're able to get get it back in correctly.

Might cover the hole in case it spits...

 

[nola mike]

I’m not sure how to do this because the engine mount is in the way of the crankshaft pulley. Please let me know if there is another way to do this. Thank you.

If you're sure the alt isn't the problem, you can reconnect the belt and turn the alt bolt. I usually get a crowbar and wedge it between the heads of the balancer bolts. Shouldn't take much to turn the engine with no drive, plugs, or accessories connected.

Sounds like it's half speed relative to the cranking. I'm thinking distributor bushings...

Mechanics stethoscope is like $5. Can touch it to the base and crank, or just pull the distributor assuming you're able to get get it back in correctly.

Might cover the hole in case it spits...

My ears aren't that precise, but I like the idea of just pulling the distributor.

 

[Scott Danforth]

remember, with the dizzy out, the oil pump doesnt turn, so no oil is being pumped

 

[nola mike]

remember, with the dizzy out, the oil pump doesnt turn, so no oil is being pumped

Turning it by hand shouldn't do much

 

[1997BR176]

Sounds like it's half speed relative to the cranking. I'm thinking distributor bushings...

Mechanics stethoscope is like $5.

I got this yesterday and can’t really pinpoint because when the engine is spinning without plugs, the noise isn’t there.

 

[1997BR176]

remember, with the dizzy out, the oil pump doesnt turn, so no oil is being pumped

So don’t spin the engine while the distributor is out, correct? Just inspect when I take out?

 

[1997BR176]

My ears aren't that precise, but I like the idea of just pulling the distributor.

By this, I assume take the whole thing out, not just the cap, correct?

 

[1997BR176]

Got the distributor out and it seems ok but not sure if there’s anything specific I need to look for

Below is the hole showing the brass bushing and it also looks ok.

https://youtube.com/shorts/Fek7AtbvbWE?feature=share

 

[Sunburn71]

In my opinion, If you've eliminated accessories, outdrive, starter , et cetera, you are looking at a siezing bearing internal to the engine. The fact that an oil treatment seems to have made a difference is telling. I would pull the motor and disassemble it to diagnose things. You might get lucky and not have to completely overhaul it.

 

[Paintman1960]

In my opinion, If you've eliminated accessories, outdrive, starter , et cetera, you are looking at a siezing bearing internal to the engine. The fact that an oil treatment seems to have made a difference is telling. I would pull the motor and disassemble it to diagnose things. You might get lucky and not have to completely overhaul it.

 

[Paintman1960]

"Might" is the Key word there, If that's what's happening

 

[Sunburn71]

After listening to the last 2 videos again, I think it sounds like it's got a knock and a squeak. Not good. You might be able to narrow down which one it is (if it's a connecting rod bearing) by pulling one plug (at a time) and running it on 3 cylinders (or pulling one plug wire at a time).

 

[1997BR176]

You can put a socket on the alternator nut and rotate the motor.
You will probably have to put tension on the belt with your hand to stop it from slipping.

No matter how tight I get the belt, I couldn’t get the engine to turn over with the alternator bolt. My question at this state where the engine is (see pic), would it spew oil all over if I try to use the starter to crank it?

 

[1997BR176]

Also, I just now paid closer attention to this vid that I took the first time when I took the outdrive out, you could hear that sound is somewhat the same just a bit faint cause it was when the plugs were out. Is it possible that I should look into the flywheel/coupler area more closely first before I take the engine out of the boat?

 

[1997BR176]

In my opinion, If you've eliminated accessories, outdrive, starter , et cetera, you are looking at a siezing bearing internal to the engine. The fact that an oil treatment seems to have made a difference is telling. I would pull the motor and disassemble it to diagnose things. You might get lucky and not have to completely overhaul it.

Yes, I was thinking with me adding the STP oil treatment helping to keep the engine running instead of that noise stopping the engine makes me think it is internal. Or, whatever that is snagging in the flywheel area (ie a bolt head, etc) just cut through enough that it was allowing the engine to also continue to run. I’m not sure, still trying to figure it out.
Thank you for the continued help, everyone. I really appreciate it.