High Pitch Rattle on a K321

[Ambush]

So over the last few months I've been building a loader on my 149. Before I started pulling stuff off there was a fairly high pitched rattle. Not a real squeal or rattle but kind of a combination. The drive line was in poor shape and the pto was sorta seized sorta not and I was pretty sure that's where the noise was from. It sounded exterior, but I couldn't pin point where exactly it was coming from. I fixed the driveline and removed the pto completely. When I fired it up today, to my surprise and dismay, the noise was still there. It sounds a bit like a dry bearing. I loosen the SG belt and that didn't change anything.

The tractor is new to me since fall with just an hour or so of run time and the noise was there when I bought it. Didn't have my hearing aids in when I looked at it and I don't hear high pitches. I don't hear women or children well and I'm ok with that.

I have no experience with Kohler's or actually any large single engines other than old motorcycles.

Is there a likely culprit, something common with this engine?

[crazycubtrio]

Your noise wouldn’t be the shroud screen bent or loose enough to make the sound you are hearing could it?

[Cub Cadet 123]

Try standing in front of the engine and listening for it and then stand behind the engine and listen for it. Like the Doppler Effect, you should hear it louder on one end or the other. Try disengaging your manual pto lever once it is running. Chances are it is in your front pto and it could just be the wear button.

EDIT: OOppsss......ignore my comment. I just re-read your post and realized that you have your pto removed from your engine so it cannot be that.

Cub Cadet 123

[Ambush]

I checked and that screen does rattle when I tap it with my finger. The bolts are snug but the screen is dimpled in under the bolts. Hopefully that's it. I'll find out tomorrow.

[finsruskw]

Have you had this engine apart?

1st thing that comes to mind...
Cam end play not properly shimmed as in to loose?
Take a long screwdriver and hold it tight to your ear and place the end on the engine. May help to ear plug the other ear while doing this.

Try it on the cam side, front and back, may help to locate where the noise is coming from.

BTW, I'm in the same hearing boat as you.

[Cubcadet_107]

Perhaps the noise resides in your S/G? What is the condition of the brushes and bearing(s)?

Or maybe the head gasket is blown?

Or one of the cooling shroud panels is loose? There's a lot of panels that could loosen up and rattle.

Just throwing out some suggestions. These Kohlers do shake pretty good, the rattle could be coming from somewhere on the tractor frame rattling due to the engine vibration.

[Ambush]

Thanks for the ideas. I really should have taken care of this problem before, but I casually and lazily just assumed what it was. Now I have to work around a loader.

I have not had the engine apart, but that doesn't mean PO's haven't. I did use a hose in my ear previous to fixing the driveline and removing all the PTO pulley and related linkages. Couldn't pin point anything that way.

I'll start with the easy and remove the drive shaft, the screen and all the top/side shrouding. Hopefully I won't need the screwdriver stethoscope to determine inner failings. The engine is a smoker, so there is work to be done there, but I thought the ability to fog for mosquitos might be nice when tilling on those warm bug filled evenings.

I have a gasket set that has a cheap head gasket and I bought a good gasket separately, so I'm going to pop the head just for inspection purposes anyway.

[Ambush]

So I took tin off the engine one piece at a time, then the drive shaft, then the flywheel screen with no luck. The noise goes away at idle. Gets quite loud just above idle then changes pitch as throttle is increased. I'm pretty sure it's coming from the front (of the tractor) but I can't pinpoint it with the redneck stethoscope.

I have .010" crankshaft end play.

The motor doesn't shake badly, I don't think.

Could it be counter balance weights or possibly the ACR?

Or maybe the governor internals?

Anyway, looks like I'm going to be pulling the motor.

[darkminion_17]

May be the crankshaft bearing.

[Ambush]

^^^ That is a possibility and not as bad a some other things, I guess

I mounted a hydraulic pump with a love joy coupling to the front. of the crank. While I was cycling the loader, don’t think there was any change in the noise with the added load.