Dirt ingestion

[outdoorpowermike]

The Kohler motor has a vent tube that goes under the plastic air filter housing and will dry and crack then fall off and suck anything in. Maybe check there.

 

[slomo]

Years ago I put a "fingerprint" of grease inside the clean side of a motorcycle intake wearing a K&N air filter. Checked a couple weeks later to find the fingerprint full of grit. The K&N went in the trash. Genuine Honda paper filter, same test, passed.

Smart man. Seen the same thing. K&N's are the worst for anything off-road. Well on road as well. Had a 2016 suburban with a K&N. Pulled the filter to clean it once. All down the intake pipe was grit city. All that was heading right to the rings.

 

[slomo]

Grease the junction between air filter and housing to "glue" the seam and possibly catch stuff if an opening appears.

I tried the wheel bearing grease trick. Not good for under hood temps in summer or mowers. Made a mess when the oil separated from the grease.

Went full on 100% GE silicone caulk on a new filter. Air filter is now glued to the filter housing with zero chance of grit passing.

 

[VegetiveSteam]

All that was heading right to the rings.

Yeah, and it's not doing the intake valve stems and guides any favors either.

 

[slomo]

I've not seen any issues myself. Do you know if the customer ever tries to clean the air filter with compressed air? Also, if you haven't already, you might check the breather hose for being loose or cracked.

No offense but start looking behind the air filter more often. Most filter housings are plastic. Most all of us over torque the screws warping the plastic. Filter material is worse and worse.

Must admit, the only clean intake manifolds I've seen are on those old pulsa jet Briggs with the foam filters. Back in the old 3.5 hp days. They were a good oiled foam filter made to last. That made to last recipe is not around today.