Engine making a loud clangy sound while running

[Red Stallion 203]

Before I start ripping things apart, my Wheelhorse 520HC has a particular loud changy/clanking sound while running. I'm guessing one of the valves are probably need adjusting as there are about 400hrs on the clock.

 

Other than that, what would be the other things I should look at? Typical of that run time?

[sqrlgtr 1,498]

Hard to diagnose without hearing it in person. Hopefully its nothing serious but I wouldn't run it until you figured out what it is. 

[c-series don 10,838]

A simple compression check might be a good start. 

[Bill D 2,453]

I'd take the drive belt off then run it briefly to see if the noise goes away.  Could be the drive belt tensioner banging.

[c-series don 10,838]

Good point @Bill D I didn’t think about that! 

[Ed Kennell 43,894]

Pull each plug wire to see if the noise is from a particular cylinder.

[sqrlgtr 1,498]

19 minutes ago, Bill D said:

I'd take the drive belt off then run it briefly to see if the noise goes away.  Could be the drive belt tensioner banging.

Could be, hope that's all it is. 

[953 nut 63,244]

I would begin by removing the engine tins to see some cute little critters have set up housekeeping in there, an acorn in contact wit a flywheel can cause quite a racket.

Onan valve seats have been known to be troublesome. A compression check as suggested by @c-series don will let you know if this is a probable cause.

[Red Stallion 203]

Its unlikely to be any animals in there. I've spent the last year stripping it apart and blasting it clean.

 

I'll try the compression test first. My gut tells me that its only one half of something, as I'm not hearing the sort of frequency that correlates to engine speed.

 

I'll also check the tensioner. That's a nice easy thing to check.

[peter lena 9,585]

@sqrlgtr   hate those tiny bearing idler pulleys , consistent   noise / failure  , lubrication failure is assured , also helps to  eat  pto drive clutch ,pete 

[Blasterdad 3,125]

I just repowered my my C-161 snow machine, when I started it there was a racket from hell, turned out I left one bolt loose on the belt guard. 

Hopefully yours is something silly simple too...