Sporadic/Intermittent Engine Noise

[The Push mower]

Here is the audio file: https://jumpshare.com/s/qi2QZkdC9OLszqa7q5iJ

Model: 44P777
Type: 0784 B1
Code 100203YG
Hours: 657

Engine is making a concerning noise and having a bit of trouble getting the engine to idle down. Best way to generate the noise is to let the governor run the engine up a bit then force the throttle lever up to touch the idle set screw then the sporadic/intermittent "clunking" will occur. I have attached an audio file where this "clunking" is present starting around 18 seconds. Note: when the idle kicks up a bit that is me allowing the governor to take over, then when the idle comes back down I am forcing the throttle lever to the idle set screw.

Thanks for any input.

 

[ILENGINE]

Idle speed seems fine to me. This engine most likely has a governored idle, so engine speed is being controlled by idle governor spring and governor system. The clunking could be a sticky issue with the electric clutch and tapping on the antirotate bracket. Or could be a drive belt/idler pulley issue that is causing some noises.

 

[Auto Doc's]

Here is the audio file: https://jumpshare.com/s/qi2QZkdC9OLszqa7q5iJ

Model: 44P777
Type: 0784 B1
Code 100203YG
Hours: 657

Engine is making a concerning noise and having a bit of trouble getting the engine to idle down. Best way to generate the noise is to let the governor run the engine up a bit then force the throttle lever up to touch the idle set screw then the sporadic/intermittent "clunking" will occur. I have attached an audio file where this "clunking" is present starting around 18 seconds. Note: when the idle kicks up a bit that is me allowing the governor to take over, then when the idle comes back down I am forcing the throttle lever to the idle set screw.

Thanks for any input.

Sounds like a worn connecting rod all throughout the audio with a little kit of piston slap every now and then.

Where are you hold the mic when recording? Are you moving around?

A quick listening device is a 3-foot section of 3/4 hose. Hold one end against your ear while you move the other end around to pinpoint the noise.

This engine does not show to have an internal balancer assembly according to Parts Tree.

Maybe the PTO clutch bolt has come loose, and the PTO is randomly knocking on the crank keyway.

Edit: Pull the rocker covers off and check for pushrod wear and the valve lash adjustment. Valves with excess lash can make some random clatter noises.

 

[The Push mower]

Thanks for the ideas. I think I will remove the deck and clutch to see if that eliminates the "clunking". It does have the governor controlled idle.

The phone was recording just under the carb. and near the governor. Phone was not being moved around until the very end when I moved the phone away to end the recording.

Sounds like it is inside the engine (lower) and ....just bad.

Mower is a Cub 17WK2ACP009 (RZT50 VT)

 

[The Push mower]

I think I will remove the deck and clutch to see if that eliminates the "clunking".

Tried both and the clunking remains....ugh. Sounds like this engine is on it's last leg.