An old timer in my local tool shop told me that for engine oil in a mower the stuff sold for diesel engines was much better as it had more additives in it. As long as you got the equivalent viscosity numbers right he said it was better for the engine than the stuff sold for petrol engines. This is lubricating oil he's talking about not diesel fuel which is also often confusingly called diesel oil.
Has anyone got any thoughts on this? Clive?

John

Am I correct in thinking this is a four stroke engine? Cheers, Tony.

Yes 4 stroke. Sorry I should have made that clear.
My own thoughts are that as long the viscosity matches there won't be any problems and that the extras in diesel oil will even be better for small engines which only say get used weekly or for my MT three or four times a year!

John

I tend to always use specific sae30 oil for garden machinery use at work...even on our Honda powered machinery. Honda I believe tend to specify 10w30 or is it 10w40.?

Recently our local mower shop has been selling B&S own brand sae30 oil..I think they may use its purchase to bulk up their B&S orders.? It has a red colourant and genuinely seems to last very well in service.

I seem to think B&S did very briefly list a 10w?? multigrade as ok for their engines..could have been in the 1980s.??.but I believe then went back to listing sae30. I suspect the 10w?? was a bit too "thin"?

I do use a multigrade in our Honda powered Muck Truck power barrow as that sees short engine run time use on cold Winter days. A mower would tend to be run at warmer times of the year and for a longer duration.

At home I have tended to use sae 20w50 in lieu of sae 30 at times. In fact Suffolk engines of old used to have 20w50 as an alternative listed on the engine data plate.

I am just not at all familiar with diesel approved oils.

Clive.

Lubrication oil for a diesel engine may have more additives but do you need them for a petrol engine? I would use whatever the engine maker recommends.
Note, older engines eg Villiers, JAp etc very often used Castrol XL or similar monograde oils, modern multigrade oils are not recommended for these engines as the detergents can clean out the old sludge leading to blocked oil ways.