Oil

Have a 2003 17HP Briggs in a Scott Mower that I have been using 30wt regular Oil in since the beginning. 30 weight oil getting hard to find and three different people have told me I should have been using a
non-detergent oil all the time, which they have plenty of. What is the best, detergent, or non, and I assume 30 weight is correct. Do not plan on changing, just interested in the experts on this site point of view. Past information I have received has been exactly right. Thanks

Three different people are idiots.

Use detergent oil.

Detergent only. I think that whole non detergent thing started because they were afraid that the detergent would foam in engines that used a dipper/splash lube system.

Oh I love an oil thread.
Detergent oils have addatives that surround & envelope any thing in the oil that is not oil or water.
This prevents impurities forming heavy sludge and allows the filter to work better.
That is all they do, in an oil or in your washing machine or in your kitchen sink.
A detergent does not clean anything, never has & never will it simply helps the liquid to carry away the impurities by isolating them.

Non detergent oils do not have these addatives and some actually have molecules that assist binding impurities together to form really big lumps that fall to the bottom of a setteling tank.


Because of the position of the oil galleries and feeds in a vertical shaft engine and in light of the fact most get used infrequently it should always run a detergent oil .
In a horozintal shaft engine which has a deeper sump it is not quite so important so you can run a non detergent oil if it does not have a spin on oil filter or pump.

The amount of foaming has less than zero to do with detergency it is all to do with the surface tension & film strength, both of which should be high in a small engine oil.

Unfortunately advertising agents who know even less chemistry than EPA regulators see the word detergent, and remember seeing it in the kitchen cupboard when crawling along the floor drunk out of what remains of their minds and they build advertising campaigns around some thing that never happened in the first place.