Troubling Engine Noise

[Scagster]

Hello all! I was driving my Scag Tiger Cub back to my shed when all of the sudden my mower engine began making a strange knocking noise. Blades were not engaged and I check the belts but all were intact and operating fine. I do not know much about engines and wanted to ask if this sounds like an expensive problem and what the problem might be. The mower is a 2001-2005 somewhere in there and this is the second engine on it I think.

Here are a few videos of the sound:

Start up and low throttle:

Start up and higher throttle:

Any ideas?

 

[logert gogert]

you got oil in the motor?
besides that sounds like it might be coming from the exhaust.
and i dont know if its the camera, but looks like your motor is moving around alot!

 

[Scrubcadet10]

First i would check your oil level, next it does look like the engine is rocking back and forth, i would check to make sure the engine mounting bolts are tight. or not broke.

 

[ILENGINE]

First i would check your oil level, next it does look like the engine is rocking back and forth, i would check to make sure the engine mounting bolts are tight. or not broke.

And follow that up with inspecting the belts for missing chunks or something stuck in the pulley grooves.

 

[keakar]

pull valve covers and confirm one set of valves hasnt come loose, these engines will run great on just one cylinder so check the obvious most common things first like a valve adjustment coming loose

 

[Fish]

Take the top cover off and peek. Sounds like something up in there.

 

[bertsmobile1]

That is the sort of sound a pebble in the alternator makes , a broken magnet ( caused by said same pebble ) makes or a bit of stick stuck in the fan makes
Do as Fish says
Remove the flywheel if you do not see debris trapped inside the blower housing to check the alternator magnets
DO not run the mower in this condition
A single loose or cracked magnet can be removed but if left in too long will destroy the stator & usually take the rectifier with it .