Can I use automotive motor oil in my 15 hp lawn tractor ? I was using amsoil full synthectic four cycle lawnmower oil, but it's too expensive, and auto full synthetic is cheaper. I'm just guessing it would be OK, because I can't think how lawnmower oil would be better (for lawnmower engines specifically) than any automotive oil, but that's just my guess.

Yes, as long as you're using the correct viscosity, automotive oil is perfectly fine.

I've used conventional automotive SAE 30W in my two commercial mowers (17hp & 25hp Kawasaki) for years. I've had the 17hp since 2004, and it still runs like a top.

Assuming it's a 4 stroke motor, you can use automotive oil in your tractor.

For example, if the owner's manual calls for SAE 30 you can substitute OW30, 5W30, or 10W30. The multi-grade will flow faster during a cold start-up and once the engine warms up the oil it'll flow like 30 weight oil.

quote:

Originally posted by wrightd:
Can I use automotive motor oil in my 15 hp lawn tractor ? I was using amsoil full synthectic four cycle lawnmower oil, but it's too expensive, and auto full synthetic is cheaper. I'm just guessing it would be OK, because I can't think how lawnmower oil would be better (for lawnmower engines specifically) than any automotive oil, but that's just my guess.

I'm a country boy do you mean a 15hp lawn mower motor? When I hear tractor I think a real tractor. In my 65 years I've never used anything but regular old motor oil in a mower probably SAE 30 or a 10-30 is all you need.

Yes. You can get Royal Purple Synthetic 1 gallon 10W-30 for quite cheap fom Amazon. ($34?)

I just ordered a gallon. Im planning to use in my new self propelled mower. I use RP 2 stroke synthetic in chainsaws and blowers and it runs fantastic.

Walmart has Mobil 1 10W-30 full synthetic in 5qt jugs for $22.88.

What does your manual say?

I have a riding mower with a 19 HP Briggs & Stratton engine. The manual says:
"Only use high quality detergent oil rated with API service classification SF, SG, or SH."

The manual goes on to specify how to select the viscosity.

I've been using automotive motor oil in it for about 20 years and it still runs like a top.

I use Rotella 15-40.

Hah, I read the thread title fast as "Ok to use automotive motor in lawn tractor?"

Hellz yeah! Do it!!!! (and post videos)

Does the 15hp engine have a pressurized oil system?

For me, that would be the determining factor. If it doesn't, I'd stick with the Amsoil.
Look into the manual for the engine (Kholer, Briggs, etc...) if provided separately from the manual of the lawn tractor.
Save yourself the headache down the road.
Sure, the oil may be pricey for a quart or two, but at least you aren't buying oil for a Caterpillar diesel.

I have always used 10w-30w Dino oil in my lawn mowers/snow blowers with good results.

quote:

Originally posted by Warhorse:
I have always used 10w-30w Dino oil in my lawn mowers/snow blowers with good results.

When I lived in Alaska, I used 0w-30 in my snowblower (it was built after the horsepower lawsuit so it was just engine cc, but I'm betting it was 11 hp) since it flows even faster than 5w-30 (which is faster flowing than 10w-30) in cold weather (i.e. Alaska's winter). The operating manual (still have it on my HD even though I sold it 2 years ago) even had a graph in there showing operating temperatures for different oils:


I found the owner's manual for my B&S generator on my HD too (it's 11 or 12 hp) and here is the oil section:

Many small engine specific oils are fortified with zinc. Most oils had zinc but not lately. The multi viscosity oil might burn faster. I found a high zink normal oil at Walmart a while back, might have been penzoil it was reasonably priced. I prefer 30w but honestly have used 5w30 Mobil1 most of the time simply because I had it.

quote:

Originally posted by reflex/deflex 64:
Many small engine specific oils are fortified with zinc. Most oils had zinc but not lately. The multi viscosity oil might burn faster. I found a high zink normal oil at Walmart a while back, might have been penzoil it was reasonably priced. I prefer 30w but honestly have used 5w30 Mobil1 most of the time simply because I had it.

The zink was taken out of oils for gas burners with catalytic converters. Enough zinc would pass by the rings and into the combustion process to eventually damage the converter.
That's why I use Rotella. It still has the good stuff and doesn't come with the high price of the boutique stuff.

As you know the statement "doesn't use any oil" is a misnomer, any internal combustion engine will burn some oil.

Reductions in Zinc content of motor oil came about as catalytic converters were being damaged by it. Also, roller tappet camshafts started being used to reduce internal friction between the camshaft and the tappet. So, between the two reasons, oils were reformulated to take advantage of less internal friction and to lessen cat damage.

This started being an issue in the late 1990's for older cars. Camshaft wear many times was not noticed, just a factor in the car "wearing out". When it came to be a topic of discussion was for the antique and hot rodders. At that time it was said to use a Diesel rated oil, more anti-scuff and anti-wear materials in that instead of gasoline rated oils.

Soon this was to change soon for Diesels also, newer more sophisticated cats on those also were now a consideration.

Comp Cams, as many of you know is a manufacturer of performance parts. They were having many warranty claims for flat camshafts. While engines can be retrofitted for roller tappets, many prefer to use flat tappets for many reasons. Well, Comp Cams warrantied these but started investigating as they thought it was a bad batch of camshaft blanks.

Further studies and oil testing found that the new oils were lacking more than the older versions of anti friction additives. Hence some oil marketers stepped up with oils being designed for the "vintage" cars. Some make "pour in" additives, choice of the user. In the two cars I have with flat tappet camshafts, a '71 (engine anyways) and a '67, they both get Valvoline VR-1. That is a high zinc oil.

Harley Davidson for one recommends the use of their own brand oil (surprise) but also stated in owners manuals that Diesel oil can be added in an emergency as it closely mimics the additives that they require. That was a few years ago, I have not looked in a newer owner's manual to see what their take is presently.

Just my opinion, not an engineer, but I would (and do) use a power equipment rated motor oil in my JD X300, my snowblower and my Coleman generator. The Deere is nine years old, the Craftsman snowblower is fourteen and the generator is fifteen years old. It may be a couple bucks more expensive per quart but still cheaper than a rebuild.

quote:

Originally posted by .38supersig:
Does the 15hp engine have a pressurized oil system?

How does that change oil choice?

quote:

Originally posted by shovelhead:
Just my opinion, not an engineer, but I would (and do) use a power equipment rated motor oil in my JD X300, my snowblower and my Coleman generator.

I'll preface this by saying that lubes are not the part of the oil & gas business that I'm in, but I am an engineer and know people in the business. Lube plants are pretty interesting to tour and see the automated filling and packaging. Also, pretty interesting to see the base stocks as well as seeing the additive stocks.

A man with no hands can count on his fingers the number of lube plants that John Deere, Briggs & Stratton, Toro, Craftsman, etc. own or operate.

Dunno. The 16HP, 2 cyl. Kohler in my mower specifies simply "10W30" for above-freezing temperatures. I've been putting plain old Quaker State in it. Still going after twenty years or so.

I run Mobil 1 10w-50 in my Ferris after talking to several pros who do the same. It's a high zinc automotive oil.

I use oils specifically made for the particular application. I use oil rated for wet clutch motorcycles in my motocycles. I use the Kohler labeled oil in my small engines (eXmark mower, Honda pressure washer, Honda trim mower, three generators). I use whatever automotive oil my cars require and oil the meets Ford's 6.7 diesel spec. I even pony up for the Polaris oil for the super charged Sea-Doo.

With all the changes made to automotive oils to meet emissions and fuel economy regulations, I just don't believe saving a couple bucks on oil in my other engines is worth it.