Changed oil in splash lubricated B&S at 25 hours

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Apr 5, 2005
There was some recent discussion about splash lubricated B&S OCIs.

I like to change mine at 25 hrs (twice a season), and I just reached 25 hrs today.

Changed the oil in my 2013 17.5HP 500cc B&S PowerBuilt Intek w/o oil filter running 5W30 Formula Shell Full Synthetic. 48.6 total hours on the engine. Oil was previously changed at the end of last season.

Ran the used oil through a #4 coffee filter. Saw nothing in the filter.

1) The filter became saturated with some kind of very fine particles, and would not pass the last 1/4 cup of oil. Tried to take a picture, but basically looks like a filter soaked with used oil.
2) I am using a magnetic NPT drain plug, and it had about a 1/16" buildup of very fine metal filings on the tip.

I am planning to stick with 25 hr OCIs, because thats my comfort level. But, I can really see no reason not to run the recommended 50 hr OCI. 100 hrs seems to be stretching things, though.
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How many oil changes has it had since new? Could still be some break-in debris in there.
The only thing less than ideal about using PCMO is that it is light on ZDDP. I don't know if it's actually necessary but lawnmower oil like B&S's own contains about 1,000 ppm of Phos'.

Dedicated lawnmower oil is of course cheaper than synthetic oil nevertheless I've never used it myself. Since I like to keep the Phos' level over 900 ppm even with some of light oils I use in my older cars (I add RL Break-In additive), I tend to use some under used oil from one of my cars in my lawnmover.
I don't think my lawnmover has had the benefit of totally fresh oil in 20 years!
I'm not a fan of oil additives, IMO crankcase's are made for oil !
But I agree with the ideology of the higher ZDDP level and would be using Rotella T5 or some type of HDEO that has the CI/CJ cross rating. I see no real need to use a full syn in my small engines, I bought a new power washer last year, it has a "breaks and scatters" on it (B&S) IIRC it's 10hp (and NO oil drain plug
) , I ran the oil that came with it for 25hrs than straight to T5. I do the same OCI's as you (generally speaking) and have the particle's also....
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