Small engine oil thread

[KNINE]

It's getting to be that time of year to bring the lawn equipment out again. Here are some thoughts I was kicking around in my K-NINE head.I have a 20 h.p. lawn tractor with a 2 cylinder Briggs and Straton. I also have a 5500 kw generator with a 10 h.p. one cylinder Tecumsa, and a 5 h.p. one cylinder B&S roto tiller. All three engines require SAE 30 motor oil. So here's my questions.Wouldn't 10w 30 oil be better? It is thinner at start up than straight 30.Would synthetic be better than dino? These are air cooled engines, and synthetic stands up to heat better than dino. I would think synthetic would offer superior protection in non water cooled engines where the temp is not regulated.Any thoughts?

[Raven]

I use synthetic oil in all my small engines. I even use synthetic 2-stroke in my dirt bike. Most small engine manufacturers recommend SAE 30. I think it's because the warm-up time is only a few seconds compared to many minutes for a liquid cooled car engine. The 30 weight offers more stability in viscousity. Most people don't change their small engine oil nearly enough. They only hold a couple of dollars of oil and it's cheap insurance to change it often, especially in hot dusty conditions.

[djb383]

It costs a lot of money to re-write an owners manual so mfgs. just call 30+ year old instructions 'good enough' and leave it like it has been. Any XXW-30 multi-weight oil will provide better protection than straight 30 and at operating temp 0W,5W,10W-30 is the same viscosity as straight 30. Synthetic oil offers superior protection under extreme operating conditions (especially at start-up when at less than operating temp) but with regard to being "more slippery" than conventional oil, it's only slightly more.

[mspalmer]

I bought a nice gas edger fom Sears at the end of last season and their manual actually suggested 5W30 Synthetic as being the best for this edger. Lucikily, I had some Mobil-1 left from an oil change and it seemed to run well.

[ToolGuy]

I use 5W-30 in my mower and snow thrower because it is technically an all temp weight oil. I also use Synthetic in my generator. My reasoning behind the Mobil1 synthetic in the generator is these things are made to run for hours on end and in very hot or very cold temps. I want the oil to last, not be burned if any, be able to take any temp outside running and when I store it, last longer than conventional. A small engine place told me synthetic is just fine for them too...I also change out all the oil before the end of which ever season that way all the dirt and garbage do not sit in the crankcase all off season. I store my Corvette that same way.

[prathman]

Yes, I haven't really understood the long-standing recommendation for straight 30 wt. oils in small engines. I think it got started back when there were some stability concerns with multi-viscosity oils - especially since some people leave the same oil in these small motors for very long periods of time. Given the short warmup time of a small engine, the makers probably figured they'd rather have a consistent 30 wt. rather than take the chance on an old multi-viscosity oil that may have thinned down to 20, 10, or even lower wt. over time.But a good 10W-30, 5W-30, or even 0W-30 oil should protect better during warmup and just as well while running as the recommended straight 30.

[Raven]

Isn't that called plagiarism?