This is the one that came with mine
My O'28 has the M-12 engine and it came with a Fram PH2849A oil filter. That's all I have used for every oil change and so far it has worked just fine. I would think that our engines are similar; 2 cylinder 10/12 HP, so that filter would be a suitable replacement. With the cockpit seat open for light and the oil filler cap off, I can see right down into my engine. It is clean as a whistle. PM