Which oil for new Kawasaki engine FR730V on a Cub Cadet Lawnmower


Thread starter
Jun 6, 2015
Winnipeg,MB, Canada
Just bought a Cub Cadet Z Force SX Zero turn lawn mower which has Kawasaki FR730V engine.
Manual says following. I have two questions
1) I am not sure what will they fill from the dealership but I want to dump that within first 5 hours. Then after, what is recommended for summer long? This chart and the language below is a bit confusing. Should I go 10W40 or 20W50? My Summer temperatures in Manitoba Canada will never be below 0 Deg C and not expected to go above 35 deg C. Will 20W50 give better protection and engine longevity on this new engine?
2) I am planning to use this equipment in the winter as well. I will remove mower deck and put a snowplow. Our temps in Manitoba are well below 0 deg C and can go as deep as -35 deg C. I am planning to dump the oil form point 1 above ( whether 10W40 or 20W50) in the fall and change to lower viscosity oil. Manual is saying 5W20 but can I go 5W30 instead? I mean the second number is only for viscosity as operating temperature. That way my Ariens snow blower and the Cub Cadet Snow plw can take sam eoil 5W30 and I dont need to buy yet another 5W20 oil.

If it were mine, 15w50 in the summer, and 0w40 for winter. In fact, this is what I run in my Kohler Command Pro.

I seem to remember Kawasaki pushing w50 oils in their OPE engines. I'll try to dig up a link that backs my claim.
You could use the recommened 10W-40 in the winter if its kept in a warmish garage upon startup. If not, that mentioned 0W-40 would be perfect.

In fact, a 0W-40 or 5W-40 could be used year-round, I suppose! Mobil-1, Castrol, Valvoline, Petro Canada, or MotoMaster products would work.

Enjoy the new machine.
I'd use a quality 5W-40 synthetic and change at 100 hour intervals. The suggestion above for T6 is a very good one.

To be more specific, air cooled engines operated in warm temperatures require an HTHS of 3.8 or higher. This is due to the relatively uncontrolled oil temperature, which can easily reach 260F or 127C on warm days. T6 5W-40 has an HTHS of about 4.5 or so. Which is a very nice cushion for hard working air cooled engines. It's a quality synthetic too, so it's pour point is -51F.
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Go 15W-50 or 20W-50. I am one of the victims of Kawasaki’s misguided 10W-30 recommendation. My FR730V was consuming oil by the 100 hour mark despite oil changes at 5 hours and every 25 after that with full synthetic oil. Don’t go thin with these motors (this is coming from someone running 0W-16 in his daily driver).
Thanks, I am still analyzing and I still have few weeks to decide as the new mower will be delivered on wednesday and I will change the oil after 5 hours of use. That should take me another 2 weeks. I have few followup questions.
1) in xxWyy the first number xx is for startup so I get it that for winter months you want to go a low number on that 5W or 0W v/s lets say 15W as I hope 5W will make the oil flow faster in the very cold temperatures ( lets say -20 deg C which is very common at my place) but I am not sure what is the opposite equation. What harm a 5W or 0W do if the engine is started in the +20 deg C. Startup is only few minutes, it will still flow easily. So why did the manufacturer not let the first number at 5W for all ranges from -30 Deg C to + 30 deg C
2) The second number yy is for operating temperatures. In my opinion once you reached full operating temperatures of the engine, how does it matter if it is in +20 deg C or - 20 deg C? if an engine needs W40 in the warmer months , should it not just take W40 in the cold months ?

Considering this if I chose 5W40 or 0W40 it should server me well all seasons but as you see that grade oil is not even specified. Should I stick to 10W40 summer and 5W20 for winter till the warranty is over?