Synthetic oil bad in a lawnmower? Any truth in this self proclaimed experts statements?

MolaKule

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I had a disagreement with someone on another forum that specializes in lawn equipment/small engines about whether or not full synthetic oil is dangerous to use in a lawnmower engine. They made all kinds of statements that didn't seem right to me. I'm wondering if some of the actual professional lubrication experts on this board like Molakule or others could read some of what he's said and tell me if there is any truth in it. The only source he could give me had nothing to do with synthetic vs conventional and was the basics of fluid dynamics, which obviously I don't have experience with or time to learn at this point. All of what I learned about oil has come from this forum over the past 15-20 years of casual reading. Here are 2 posts from this guy on the thread discussing use of synthetic in a lawnmower engine:

You will find that in OLDS as well no maths required."

I think my grandson's German Shepard could put together a more constructive article than this and still stay on point.

Unbelievable and extremely uninformed.
 
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No, Synthetic oil does not have any detrimental effect on modern engines (last 20 yrs). That’s from a manufacturer....
 
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That’s from B&S. Curious if any others still spec a conventional oil and if so, why?
If they do it's because it doesn't matter, at least not very much.

Considering that most synthetics are majority Group III base stocks, that makes the overall composition of the oil identical to a "conventional", whatever that means these days.
 
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In my TAFE classe I used to ask the question
What is the purpose of the detergent molecules in oil ?
In the 11 years I taught not s single student got the question correct
We put the same question in the final exam and agin just about every student got it wrong
They all correctly described the mechanism of how they work but the students could not get the "detergents clean" BS out of their heads that the advertising companies had implanted .
And if you are wondering.
The function of the detergent is to carry away the particulates that they encounter & prevent them from combining
Secondary purpose is to make the contaminants close to the SG of the base oil so they will circulate freely within the oil to facilitate mechanical removal .
You will find that in OLDS as well no maths required."
This is my favorite part. Do soaps and detergents clean? Yes. How do they clean? "By carrying away particles and prevent[ing] them from combining. To be more specific, detergent/soap molecules surround the "dirty" particles and encapsulate them. The encapsulated dirt/oil is now can't combine with other similar particles and just float around in the oil. These outside of these encapsulated clusters also have more affinity for water than oil, which is why they rinse off in water. This is exactly how detergent gets grease and dirt out of your clothes and off your hands.

So detergents "cleaning" oil is a perfectly valid answer. Trapping dirt so it can't accumulate is cleaning. You seem to be asking HOW they work. That's a very different question.
 
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Dispersants do sequester particles but the general term “detergent” as related to motor oils means more than that. It’s actually not a very good term for all the things that “detergents” do.
 
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Oil pressure in a lawn mower?? Proved their ignorance right there! I don't think most (non-arctic operated) OPE NEEDS full synthetic, but I can't see it hurting anything.
Sorry I have to be this guy. Some push mowers had oil pumps right? The Tecumseh 4 cycle found on many Lawn Boys for example although that’s all I knew about.
 
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Most of not all 5w30 is some sort of blend apparently. On top of that, a lot of OPE branded oils are full synthetic.
 

350Rocket

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My Kohler has a filter and pump although it might still be partially splash lubrication, I haven't been concerned enough about that to look it up. Either way I know the engine will be fine on the existing 10w30 vr1 or 20w50 in conventional or synthetic, or m1 0w40 that I run in everything else (which currently seems it be out of stock everywhere local). I was half a qt short for my truck after changing the oil in the Oldsmobile and the snowblower so I had to top it off with Castrol 0w40.
Sorry I have to be this guy. Some push mowers had oil pumps right? The Tecumseh 4 cycle found on many Lawn Boys for example although that’s all I knew about.
 
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Put Synthetic oil in my snow king and it started leaking here and there. So I dumped it.
This is back when during the "Tri Synthetic Formula days. Same deal in my Yaris during the fake synthetic period. but I just let it weep.

I don't anticipate any issue with the CHonda** power Toro this fall. I think I put 10W30 QSUD in there.
_____________________________
**LONCHIN 中国制造
 

350Rocket

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One time I ran synthetic in my old John Deere push mower and I hit a rock which bent the crank and ruined the motor. So turns out that guy was right about synthetic.
Lol that's exactly how it took out my 81 3hp Briggs but it was a huge bolt. It already had a million fights with rocks at my parents place and even broke the flange that holds the blade on once. Right before I bent the crank it didn't smoke at all and ran better than my current 99 6hp quantum which smokes every cold startup and is slightly stinkier than the old one. I tried straight 30w I got for free just to see if it helped the smoke and it almost seemed worse so I went back to whatever mobil 1 synthetic I had on me. Either 5w30 EP high mileage or 0w40 Euro. It runs the same on all of them and doesn't use any oil despite the smoke on startup.
My 300 hour Kohler doesn't seem to burn any oil so far but I've only put 18 hours or so on it. No previous maintenance history but the oil looked good before I changed it.
 
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Good to know for my straight eight OPE. Think I'll keep using the same snythetics I use in the cars and motorcycles. Keeping the crankcase filled and proper change intervals are the most important factors.
 
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A lot of the manufacturers are now recommending synthetic oils such as B&S and Kawasaki. Briggs depending on the engine and operating conditions they recommend a synthetic 5w30 or 15w50, Kawasaki mostly recommends 10w40 or 20w50, I believe that Kawasaki even extends the warranty if you can prove that you don't use 30w oil.
 

350Rocket

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A lot of the manufacturers are now recommending synthetic oils such as B&S and Kawasaki. Briggs depending on the engine and operating conditions they recommend a synthetic 5w30 or 15w50, Kawasaki mostly recommends 10w40 or 20w50, I believe that Kawasaki even extends the warranty if you can prove that you don't use 30w oil.
I just got a champion 5500watt generator and while it recommends 5w30 not specifically synthetic...the synthetic 5w30 covers the widest range of temperatures so that in itself is kind of endorsing the synthetic. Several other grades such as 10w40 were also allowed for certain temperature ranges.
My snowblower just says 5w30 synthetic if I remember right.
 
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Sorry I have to be this guy. Some push mowers had oil pumps right? The Tecumseh 4 cycle found on many Lawn Boys for example although that’s all I knew about.
All it did was move oil to the top crank bearing. I think there were some other brands that did similar. Some with filters only pumped the oil through the filter.
 
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I have a craftsman push mower that the family bought new in 2008. It's still kicking with never having had an oil change (and yeah the oil is black and gross-I can probably count on one hand how many times it's been topped off) but honestly a splash lube engine doesn't seem to care as long as there is lubricant in there. The deck is about rotten apart now so we wouldn't have gotten any extra life out of it with regular changes.

I may patch the deck with my welder since it still starts right up just to see how long it can go (have other more maintained equipment to use)
 
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