So, older Troy built lower self propelled. Haven't changed oil in it for 4.5 years. Have some straight 30 and tons of PYB 30&40 straight grade. Which would you folks use? Thank you in advance
Andrew
Personally I have been using nothing but conventional PCMo straight #30 oil in my and my customers mowers for over 40 years. Summer use only of course. Snowblowers get 5w30.
I think any old 30 weight oil would be fine. Not much cutting grass in cold weather. And for me not much cutting grass if its super hot out either, but more of an operator issue than a mower issue.
While your changing your oil, blow out all the dried grass and mouse nests clinging to the engine cooling fins. Might be more important than what oil your using.
I have used many oils in a push mower including PYB 30, FS 30, and T5 10w30 Rotella Blend. The last 3 years I have used the T5 and change it once a year. It is in amazing shape every time I drain it. It is almost brand new looking throughout it's service (1 year/ used in the summer).
I'd use either one myself, both are good. Maybe I lean a little more toward Rotella with a robust add pack for my mower & generator. Calls for 10-30 on both. I use Rotella 5w-40 or 15w-40 though.
Merkava: you would be proud of me today, I put some of the circa 1980's HD-40 Pennzoil in the aunts GOODALL push mower. It's really smooth and runs great!