40 weight oil for ail cooled mower?

[Jake54]

What are some thoughts on using 40 weight oil with an air cooled mower during the heat of the summer?
The engine is a 675 Engine Series Briggs & Stratton with assist pull.
Just rescently got the mower up and running after a good 6 years with it sitting outside. changed the old oil once, put new 5w30 in it, changed that out after an hour of use in 95*F plus heat, put 15w40 in it after the second drain.

 

[Skittles]

Originally Posted By: Jake54
What are some thoughts on using 40 weight oil with an air cooled mower during the heat of the summer?
The engine is a 675 Engine Series Briggs & Stratton with assist pull.
Just rescently got the mower up and running after a good 6 years with it sitting outside. changed the old oil once, put new 5w30 in it, changed that out after an hour of use in 95*F plus heat, put 15w40 in it after the second drain.


It won't matter.

 

[Rand]

it will run fine.

thicker should be fine but thinner maybe not so much.


IIRC those spec'ed 5w30 syn, or straight 30wt conventional.

I'd avoid a 5w20, or anything thicker than 15w40

 

[Quest]

I've been using Chevron Delo 15W40 on all B&S air-cooled engines, including my dad's B&S 5hp sidedraft, 675 series side-draft, Honda engined pressure washer, etc.

Use 15W40 with confidence.

Q.

 

[tig1]

I use Mobil 1 10w30 in all my OPE and have for 20-30 years. Never had a problem.

 

[Jake54]

a big reason why i'm using 15w40 is because my step-dad's a farmer, so there's an abundant supply of it around.

 

[HerrStig]

I ran 20W 50 in a Tecumseh powered mower and it lasted about 15 years. The body finally rusted out with the engine still OK.

 

[JTK]

I've used 15w40 in place of SAE30 for my small summer time used air cooled OPE for years. I feel it's a better oil, better choice.

For extreme heat, I'd use 20w50.

 

[THORROMIG]

Running 10W40 Defy for the last 3 years. Got 13 quarts for a dollar apiece at an Autozone clearance back in 2012.

 

[NH73]

15w40 is better than straight 40 weight

 

[Lawn_Care]

I run 15w40 in the summer, and 5W-40 in the cooler months in all my OPE and small engines. Have ran 40-weights for years in air cooled engines without problems.

 

[jhellwig]

Originally Posted By: NH73
15w40 is better than straight 40 weight


No.

 

[MolaKule]

It will run hotter with an SAE 40 grade.

Stick with a good synthetic 5W30/10W30.

 

[Jake54]

I thought about switching to a synthetic just for the engine to run cooler in general. but I might just leave the oil that's in there now until next year because the push mower I put the 15w40 in is just to mow places the riding mower can't get to, so literally 30 min max every week, not very hard use at all.
Originally Posted By: MolaKule
It will run hotter with an SAE 40 grade.

Stick with a good synthetic 5W30/10W30.

 

[Bror Jace]

"15W-40 is better than straight 40 weight."

Agree. Better at start-up, better add-pack almost every time. If you are breaking down and thinning out 15w40, please let us know.

"I've used 15w40 in place of SAE30 for my small summer time used air cooled OPE for years. I feel it's a better oil, better choice."

Agree again. I like 15w40 for hot weather use in OPE. The only time I'd pick a 10w30 HDEO or synthetic if the engine is brand new AND the temps are not that hot ... no more than 80s (F) and my time operating the machine is less than 2 hours.

Torturing an OPE engine in the summer? 15w40 is a top choice.

 

[Jake54]

While we're on the subject of oil in mowers, I've got a liquid cooled John Deere 425, I put 10w30 in it because it's liquid cooled (and that's what it calls for)

 

[SR5]

10 years ago I got a new push mower with an air-cooled B&S engine. The mower was sold dry and from memory the booked called for a straight 30wt oil. I didn't have any.

I did have lots of Castrol GTX 20W-50, so that went in. I mowed the yard, about 3-4 hours, then drained the first lot of oil and put in a second fill of GTX.

It's been running on GTX 20W-50 with annual oil changes since then. Ten years later the engine is fine, but the body is broken. My yard is pretty rough and I really have to throw that mower around.