Splash lubrication of horizontal mower engine

[DrRoughneck]

A few questions about horizontal one-cylinder engines in your typical push-mower
- Since "splash lubrication" is used (as it seems to be the most common way), it would seem much harder to splash the top part of the piston (fighting gravity) and that the top part of the cylinder would be prone to lack of lubrication. Is it your experience?
- These engines usually have a "peak RPM". Is this the sweet spot of RPMs where splash lubrication works best (where oil gets splashed the highest)? My mower also has an idle throttle adjustment where the engine runs at much lower RPM. Does it then run the risk of improper lubrication?

 

[old1]

Even at idle speed, the oil in the crankcase, (not just the sump) is virtually a mist, covering EVERYTHING inside the engine. To demonstrate, just pull out the dipstick sometime with the engine running.

 

[DrRoughneck]

Originally Posted By: old1
Even at idle speed, the oil in the crankcase, (not just the sump) is virtually a mist, covering EVERYTHING inside the engine. To demonstrate, just pull out the dipstick sometime with the engine running.

Makes sense thanks.

 

[CR94]

Now the opposite question: How do cheap vertical-shaft mower engines splash oil up from the sump?

 

[DrRoughneck]

This is how the "oil slinger" works:

 

[Donald]

Your mower deck is going to rust out or carb gum up or neighbor gets newer mower than you have. You will get a new mower before the engine bearings or cylinder walls wear to the point of failure. Assuming not a commercial user and you maintain it properly. Flat head splash lubricated engines have been around for a long time. They are beasts. With non-points ignition they only need a once-and-awhile oil change and E0 or stabilized gas to run for a long time.

Years ago some people had gas powered reel mowers with horizontal shaft engines. Find one at the curb, pull the engine and build a mini-bike around it.

 

[Dave Sherman]

On that subject, how do the rocker arms get splash lubrication on an OHV vertical shaft engine? I tore down and rebuilt an old B&S flathead once, so I can see how that gets lubricated.

 

[Linctex]

Originally Posted By: Dave Sherman
On that subject, how do the rocker arms get splash lubrication on an OHV vertical shaft engine?


The oil is a virtual BLIZZARD inside the engine when running - it's amazing the breather works as well as it does separating oil from air!!

All they need is some oil mist - they don't need to take bath.