Why do mower filters have a bigger absolute micron rating?

[97K15004WD]

Fyi, I too use a car filter on my B&S 21hp engine on my JD mower, a Purolator PL10241, which has same threads & pressure bypass psi. I just remove the filter & pour out the fluid in it & replace it every oil change. These filters are good for 10k miles on a car so 10 hrs a year is nothing.

So where did you find the bypass pressure psi information?

My concern with the 3614 is exactly what repairman54 is bringing up. A low power oil pump pushing through a restrictive automotive filter. Surely the B & S engineers picked a filter media and bypass type for a reason, right?

 

[repairman54]

Not sure on the type of oil pump, piston pump or gear pump in that motor. Piston pump would not make much pressure so a more open filter media would be preferred. Positive displacement pump could handle an automotive filter.
These LG motors are mostly splash lubed no filter anyway, I don't see makers beefing up internals for any of their 3600 rpm motors anyway, filter on the bigger units would be there to try to increase longevity IMO, or at least try to.
No engine is more abused than those on LG equipment, it's amazing how long they run with dirty and low oil.

 

[jhellwig]

It doesn't matter. You could bypass the filter all together and never notice a decrease in life span before the engine wore out if you take care of stuff. Making sure the oil is always full will make much more of a difference on life than worrying about what filter to use will in this application. Very few ope engines do more than pump oil through a filter and into the crank bearings. There are some that use actual bearings and lube more than just the crank bearings but that is on higher end engines.

 

[oil pan 4]

Just a guess. They aren't concerned with anything "smaller" than 32 microns. If there is room you can run the Wix 51516 / NAPA Gold 1516 as it's 2.5" taller. I had a JD with 17HP (Kawasaki ?) and used the NAPA 1516 for 6 years. Sold it and it's still running. The oil always looked brand new, but I changed it anyway.

I'm going to go write the under the hood of my lawnmower when I get home.
Right now it's got a longer 4.75 inch long "32 micron" filter. I changed the oil 2 years ago and it's got 40 to 50 hours on the oil and still looks pretty clear. But I'll put a 51516 or 1516 when I do change it.