Oil for Riding Mowers

Status
Not open for further replies.
Joined
Jul 19, 2006
Messages
134
Location
ohio
I have 20 year old Murray 16 HP-B&S single and a 3 year old Cub Cadet 22 HP-Kohler twin.

I have always used 15-40 Rotella in my mowers .......from what I have been reading lately it seems a lot of people use 5w-30 in their mowers , but it seems a little thin for an air cooled engine.

I just wondered if I should try switching to a thinner oil ???
 
It's hard to beat what you are already using.

Conventional 5W30 will consume quite a bit in the summer. I would not use in your applications. Synthetic 5W30/10W30 is a good choice. As is SAE30.

SAE30 and 15W40 are available as heavy duty engine oils which will have a better additive package for an air cooled engine.
 
Why not try 10w-30 Rotella if you'd like to go thinner?
But if you don't mow in cold weather (so don't have starting issues with the 15w), then I'd think the possible fuel economy benefit would be offset by checking the level more often / topping up.
 
The OPE industry specifies SAE30W across the board for mowers because they assume the oil may never get changed again, and the straight weights don't suffer as much Noack volatility (evaporation) or viscosity breakdown as the multi-weights. Also most mowers usually only get used in mild to hot weather, so there is no pressing need for a multi-weight.

Your motors will be fine on almost any multi-weight, as long as you keep it topped off and change it occasionally. If you're even asking the question, I'm sure you already do this. If you're giving it to a relative with poor maintenance habits, send it full of straight 30W.

I maintain a fair number of B&S, Kohler and Tecumseh motors, and run straight 30W in all of them except the Snow King snow thrower motor, which gets 5w-30 synthetic. It is also the only motor with an owner's manual that even mentions synthetic, it's not a requirement, but it is recommended.

If I were you, I would just stick with what already works. As your motors get older and more worn, you may find more oil burning if you switch to a lighter weight oil.
 
Briggs cautions not to use oil with viscosities above 30.

Link 1 (Look under Q&A tab)


They have a chart showing their recommendations:

Link 2


Kohler also recommends 30 or xw30 oils in a chart. They don't recommend even 5W20 or 5W30 synthetics above degrees ambient. However, I've used snythetic 0W30 A3 oil in my Kohler Command Pro for 10 years with zero problems and the engine starts, sounds, and produces power like it did when new.

Link 3

It's also interesting to note that the engine oils marketed by Kohler, Briggs, and perhaps others, are typically SJ oils. Not sure why. Hard to believe they would be cheaper to produce than higher production volume oil like a current automotive SN.
 
I've had Mobil 1 TDT 5w-40 in the 26hp Briggs ELS engine on my Scag zero turn since the first oil change in 2007.
 
I've used nothing but T6 5w40 in my OPE (Briggs 4.0 flathead lawnmower engines, 28-HP Vanguard v-twin in a zero-turn, and Kohler 15 HP single in a lawn tractor) for years now. Its not a an overly heavy 40, and still has additive levels comparable to the SJ oils Briggs keeps recommending (which are only available in bargain-basement brands or OPE-specific brands).

I have no idea why they're so adamant about 30-weight, but my guess is they don't want people using cheap non-synthetic 10w40s with a ton of VII. Not a problem with a premium HD synthetic 40.
 
I run 25% NAPA 10W-30 full synthetic, and 75% NAPA 5W-30 full synthetic...

And a STP SA3600 oil filter...
(Fram 3600 equivalent)
 
Last edited:
Originally Posted By: 440Magnum
I have no idea why they're so adamant about 30-weight, but my guess is they don't want people using cheap non-synthetic 10w40s with a ton of VII. Not a problem with a premium HD synthetic 40.


Besides viscosity breakdown, they are also looking at the very low Noack of straight 30W. The general assumption is these motors will be under-maintained, and anything that better maintains the oil level, helps.
 
Originally Posted By: fins
I have 20 year old Murray 16 HP-B&S single and a 3 year old Cub Cadet 22 HP-Kohler twin.

I have always used 15-40 Rotella in my mowers .......from what I have been reading lately it seems a lot of people use 5w-30 in their mowers , but it seems a little thin for an air cooled engine.

I just wondered if I should try switching to a thinner oil ???


The main thing with small air cooled OPE engines is they have some type of motor oil in them, it's kept at a proper level and changed at a reasonable interval. Doesn't really matter if it's a 20, 30, 40 or 50wt variant if the all the above are true.

That said, I'm with you. I use 15w40 in place of SAE30. Have so for more pieces of equipment than I can count now.
 
Originally Posted By: HangFire
Originally Posted By: 440Magnum
I have no idea why they're so adamant about 30-weight, but my guess is they don't want people using cheap non-synthetic 10w40s with a ton of VII. Not a problem with a premium HD synthetic 40.


Besides viscosity breakdown, they are also looking at the very low Noack of straight 30W. The general assumption is these motors will be under-maintained, and anything that better maintains the oil level, helps.


I would believe that rationale, IF they were recommending straight 30weight. But they recommend 30, 5w30, or 10w30 pretty interchangeably. In most of the current B&S oil charts, 5w30 (sometimes specified as "synthetic") is the one recommended at all temps. There's no "synthetic" caveat applied to 10w30. Its all very outdated if you ask me, especially given that API SJ is mentioned.
 
Right, and like we've all chatted about 50x over, the old SAE30, 10w30 still holds on because it's easily recognizable to consumers, easy to get and can cover such a broad range of operating conditions.

Not to say it's the best, but the safest "bet" for the average consumer.
 
Last edited:
Originally Posted By: 440Magnum
I would believe that rationale, IF they were recommending straight 30weight. But they recommend 30, 5w30, or 10w30 pretty interchangeably. In most of the current B&S oil charts, 5w30 (sometimes specified as "synthetic") is the one recommended at all temps. There's no "synthetic" caveat applied to 10w30. Its all very outdated if you ask me, especially given that API SJ is mentioned.


They recommend conventional SAE 30, synthetic 5W30, and synthetic 10W30.

They say that conventional 5W30 can be used under 40 degrees F, and conventional 10W30 can be used up to 100 degrees F, but expect higher consumption over 80 degrees.

In use, conventional 5W30 and synthetic 5W30 are on complete opposite ends of the spectrum when used in the summer. Conventional consumes about 1-2 ounces per hour while synthetic stays on the full mark for almost an entire season.
 
Originally Posted By: old1
IMHO 5w-30 is ok as long as it is full synthetic. Personally I wouldn't change from what you have been doing.



While I agree it isn't broke so why fix it however I diasagree with the syn being a necessity.
I use a 5w-30 in our 16 5.5 hp air compressors and generators and I've got a couple with in excess of 15000 hours. Yes I wrote 15000. All my compressors are hondas. None have gotten more than plug and oil changes. Mos2 every second interval and a tc-w3/acetone home brew fuel additive.
Piston crowns are absolutely spotless. My supplier is also our service guy and insists I tell no one of my habits because of all his customers I'm the only one who never needs my machines serviced.
The regulators blow up in the winter but I'm not paying for someone to swap them out.

If only run in the summer any grade hdeo would work fine. A 30 grade would free up a bit of pep since most OPE is splash lubricated but I haven't noticed any differences in real life.
 
Originally Posted By: Brian Barnhart
Briggs cautions not to use oil with viscosities above 30...

...It's also interesting to note that the engine oils marketed by Kohler, Briggs, and perhaps others, are typically SJ oils.


I think the reason they specify an SJ is they are more interested in the AW capabilities than they are detergency.

I say use a synthetic 10W30 and call it a day.
 
German Castrol 0w30 is the perfect mower engine oil for all climates. It flows perfect at well below zero and it thick in the warm weather. It is absolutely PERFECT for OPE lubrication.
 
I use Valvoline 10w30 VR1 in my 17.5HP Briggs-powered riding mower and in my 5HP Briggs-powered rotary mower. It seems to work very well.
 
Originally Posted By: Brian Barnhart
Briggs cautions not to use oil with viscosities above 30.

Link 1 (Look under Q&A tab)


They have a chart showing their recommendations:

Link 2


Kohler also recommends 30 or xw30 oils in a chart. They don't recommend even 5W20 or 5W30 synthetics above degrees ambient. However, I've used snythetic 0W30 A3 oil in my Kohler Command Pro for 10 years with zero problems and the engine starts, sounds, and produces power like it did when new.

Link 3

It's also interesting to note that the engine oils marketed by Kohler, Briggs, and perhaps others, are typically SJ oils. Not sure why. Hard to believe they would be cheaper to produce than higher production volume oil like a current automotive SN.


You provide good information. Your links are good.

With that said, anecdotally, I can say SAE 40wt. has performed excellently for me in south TX. I think given operations in temps that are always above 75, one can safely extrapolate the charts to allow a straight 40.

In Ohio, of course, lighter weights are indeed more appropriate.
 
Mobil 1 High Mileage 10W30 for summer equipment, Mobil 1 High Mileage 5w30 for snow blowers. API SL rated, shear stable oils with extra AW additives over API SN products.
 
Status
Not open for further replies.
Back
Top