pre filters

out of curiosity do you guys put the green pre filter over your air filters on your old kohler engines i've seen some people put it on and some people don't what are your guy's preference?

I install the pre-filter on any engine I own that will see regular (dusty) service. The pre-filter stops some of the larger dust and that prolongs the effective life of the main filter.

That said, my old Kohlers on my collection Cub cadets don't have them on there because the mice were using them for bedding. Its pretty distressing to find a practically new pre-filter with chunks chewed out of it.

BTW: None of the small engine manufacturers that I am familiar with say its o.k. to blow out your air filter. They say it makes larger holes in the paper than were there originally and then the engine can ingest dirt.

I use them with an added detail that my grandfather always did and that is to saturate the foam with oil. Takes about a good table spoon, kinda wring it into the filter by hand. When it gets dry enough for lots of dust I will wash the prefilter, dry it and re-oil about every other tank of fuel.

All of the Kohler Command engines I have bought new had foam pre-filters. I will install them on any engine that does not have one if possible. When oiled properly and cleaned. They can extend the life of the air filter greatly.

I still run a couple K-series Kohlers and a B-48G Onan, and use the pre-filter wraps on them. Helps keep the actual filter cleaner a whole lot longer. The two stage canister style filter on the 27 hp Kawasaki on my Cub Cadet Tank is a "REAL air cleaner", full size, foot long inner and outer filters, just replace the outer as needed. Wish I could use the same filter on both my Farmall M and Super H. The oil bath filters suck, messy and let WAY TOO much dirt into the engines. And for all you old farts that think oil bath filters are so great, if they really were any good, don't you think the manufacturers would still be using them?

Lets face it, the additional cost and the time consuming maintenance process are probably the main reasons the oil bath air cleaners were discontinued.

The increased efficiency of newer paper filters and ease of maintenance have certainly made the old oil bath cleaners obsolete.

In 1975 the premium optional (severe service) air filter for the big Ford trucks was an oil bath air cleaner.

So.....(as an old fart).....I disagree that oil bath air cleaners (when properly maintained) allow more dirt into an engine.

Brian - I bet I could pour handfuls of sand thru the oiled mesh in the Donaldson oil bath air cleaners on
my two Farmall's.
I spent a couple days researching the filtering efficiency of different types of air filters. Pleated
paper filters like OEM's use were all 99.9% efficient at removing all sizes of dust & dirt.

Oiled cotton gauze filters were around 95%, and since they are advertised as clean able, once cleaned,
thousands of points of light shining thru the gauze leads me to think maybe 90% is the best they can
filter. I ran oil analysis on my Ford diesel pickup, with the OEM plated paper my silicon reading was
zero or 1. With the two oil tests I ran with a K&N oiled gauze drop-in filter it tested 1 or 2 rpm. Once
I cleaned & washed & dried the K&N I burned it, ran to town and bought a new OEM filter.

Now, I looked at 3-4 different brands of oil bath filters and NONE of them published filtering
efficiency. Vortex brand states a 90% filtering efficiency at 20% rated flow, and they claim to "approach
98% efficiency", but they don't say how.
None of the other oil bath filter manufactures make any kind of printed claim.

So instead of criticizing others, check for yourself. I've had the complete set of 1978 Ford F-series
truck manuals since about 1980, read them cover to cover. Yep, Ford, And most other truck manufacturers
were using oil bath air cleaners as the severe duty filter. They could not possibly have made a worse
choice. It was common, messy, and always wrong. Have you seen the size of dry pleated paper filters they
use on class 8 trucks today?

First of all I did not criticize you!
I stated my opinion.
And.......I agreed that paper filters have advanced tremendously.

Yep, Ford, And most other truck manufacturers
were using oil bath air cleaners as the severe duty filter. [color=darkblue:c999d94be0][b:c999d94be0]They could not possibly have made a worse
choice.[/b:c999d94be0][/color:c999d94be0]

If they had only consulted you before making their decision!!