Hi Gadge
I had an inkling 3300 was the top - any more than that I though was pushing it. I agree, the main issue is clearing clippings - I actually went up 2 levels at one point with a bit of improvement and then went back over.
Probably more an indication of reciprocating mass than a poor engine I suppose - the little gxv120 on the big bob is 70cc less and will go through much thicker grass (though being a side shooter it is under much less load)
I sometimes run sae30, but I an never get it at a good price - always pushing $30 for 5L. I bought a tonne of Castrol UltraClean 15w40 at autobarn for $12/5L bottle.
I use very short oil change intervals (often change after every mow until I am happy its staying clean) so at $1.40 ish per oil change with the 15w40 semi, it is quite economical. Before I put this oil in, I use the cheapest 15w40 I can find (usually Nulon or gulf western mineral) to flush the muck out for 2 or 3 changes.
In normal use, I notice no consumption. Briggs recommend 10w30 up to 37 degrees - but I reckon thats a bit too thin (can only imaging how much I would have burnt on saturday.
Apparently, 15w40 is the most shear stable multigrade.
Its only in this heavy cutting I have noticed oil consumption. Still, I believe it leaked a fair bit of this.
That being said, a friend never checks his oil so I use sae30 in his.
