OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions on Other Engines Can you use 15w oil ?

Hi guys,

Looking to get some oil for a B&S engine and (C)honda engine (trying to get them up n running). I was looking at 10w30 which seems to be recommended but pricing seems higher.. I know it's oil and important, but I didnt want to spend alot.. but have noticed some 15w oils on special.. just wondering if its ok to use 15w or is it too thick ?

Location: Sydney NSW.

15W will be fine for the Chonda - Honda recommends the 10W- stuff as a 'universal' oil, that includes operation in much lower temperature conditions than encountered in Oz. 15W40 would be a good choice.

This is the oil viscosity chart from the GXV120 workshop manual:


Briggs side-valves on the other hand [assuming this is for your Quantum] are best suited to an SAE30 monograde oil. They always seem to burn a bit of oil when run on multigrades, even 20W50.

However, 15W40 will work fine; just need to keep an eye on the level.

I'm with you there Gadge. My 16HP side valve Briggs chews through multi grade but if I use the 30W Penrite briggs approved it doesn't use a drop. I got it from tight arse auto.

As you see from the chart that multi grades allow low temp operations as the oil is thin at these temps. If operating during your Summer season then 15w40 would be fine for those engine with oil pumps and SAE30 for the oil slinger version. As note regular multi grade oils then to burn off quicker in warm weather. Now your synthetics does this at a much less of a rate.

Here something that happen here last summer on a rebuilt engine that a customer was using in 100+F temps. Within one month the came back without oil and the engine was destroyed because they insisted on SAE10w30 oil and never checked the oil level.