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

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Can you expound on that a little bit? So the oil is filtered, but isn't supplied to the crank or valvetrain by the pump. The pump just circulates oil through the filter? Not sidetracking, just not up to date on such designs. Thanks.
It varies by the manufacturer. Some engines with a filter are splash lubricated and some are fully pressurized. A lot of the engines that do have a filter simply have a small oil pump that circulates the oil through the filter only and is dropped back into the crankcase. Better than no filter at all, I guess, but the engine bearings are not pressure lubed.
 
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So the oil is filtered, but isn't supplied to the crank or valvetrain by the pump. The pump just circulates oil through the filter? Not sidetracking, just not up to date on such designs. Thanks.
Exactly. On some engines the oil pump and filter are only there to filter the oil and the actual lubrication is still splash-type. B&S is famous for doing this on many of their engine designs. I was never sold on this design because I don't think that it accomplishes much (other than adding cost, complication, weight, and physical size to the engine).
On the other hand, Tecumseh used semi-pressure lubrication on all of their vertical crankshaft 4-cycle engines. A crude oil pump was located on the bottom of the camshaft and pumped oil up to the upper camshaft and crankshaft bearings, while the connecting rod bearing was lubricated by oil mist in the crankcase, and the lower crankshaft bearing was lubricated by being totally submerged in oil.
 
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I've used Mobil 1 10W30 full synth on the same Toro Lawn Mower for the last 15 yrs and it runs like a champ!
Yes but is it bad for the mower !!! ;)
Let's not forget the if you are going from conventional oil to synthetic you must first run semi synthetic then if no leaks or oil usage you then can run synthetic. However be careful cause synthetic oil will damage seals after use of conventional oil.

You can't use synthetic oil if you used conventional oil for the early part of engine life.

Must flush engine first before you use synthetic.

Do not use 0w in Louisiana as a 10w will protect better in heat.

These are a few misconceptions I heard working at dealership.

Can you expound on that a little bit? So the oil is filtered, but isn't supplied to the crank or valvetrain by the pump. The pump just circulates oil through the filter? Not sidetracking, just not up to date on such designs. Thanks.
Yes
 
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I've only used synthetic because it's what I have on hand. Snowblowers require synthetic quite often. I've found, aside from running without oil, it's difficult to completely kill a small engine. And I've done my part in trying at times. Maybe I've just been lucky.
 
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Can you expound on that a little bit? So the oil is filtered, but isn't supplied to the crank or valvetrain by the pump. The pump just circulates oil through the filter? Not sidetracking, just not up to date on such designs. Thanks.
Most walk behind lawn mowers do not have an oil pump, only the best ones like Honda do, the rest uses the splash method.
This is something to keep in mind when selecting a unit if one has inclines.
 
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Use Syn 5W30 in all my OPE. I do dose it with "Street Legal Oil Boost" from my high ZDDP additive days (gotta get rid of the SLOB somehow).
 

350Rocket

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I've only used synthetic because it's what I have on hand. Snowblowers require synthetic quite often. I've found, aside from running without oil, it's difficult to completely kill a small engine. And I've done my part in trying at times. Maybe I've just been lucky.
I think a lot of the newer OHV ones (especially Briggs and Stratton) are not at resilient as the old ones.
 
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Most walk behind lawn mowers do not have an oil pump, only the best ones like Honda do, the rest uses the splash method.
This is something to keep in mind when selecting a unit if one has inclines.
Honda uses splash lubrication on all of their walk behind vertical crankshaft lawn mower engines and horizontal crankshaft engines. Only Honda's larger V-Twin engines have pressure lubrication. https://engines.honda.com/why/technology#
 
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Honda uses splash lubrication on all of their walk behind vertical crankshaft lawn mower engines and horizontal crankshaft engines. Only Honda's larger V-Twin engines have pressure lubrication. https://engines.honda.com/why/technology#
I think that applies to "High Capacity" oil pumps. I had a 1980 Honda walk behind self propelled and it had an oil pump, have not kept up with the tech specs, but I doubt that they would have done away with that. Anything is possible however.
 
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I think that applies to "High Capacity" oil pumps. I had a 1980 Honda walk behind self propelled and it had an oil pump, have not kept up with the tech specs, but I doubt that they would have done away with that. Anything is possible however.
The old Honda HR21 L-head engines did in-fact have an oil pump at the bottom of the camshaft and worked the same way as Tecumseh's lubrication system did. I never really understood this given the fact that the upper crankshaft bearing was a ball bearing. On the newer OHV engines Honda did away with the oil pump. An oil slinger was incorporated into the governor gear.
 
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I just bought a Toro Power Max 824 snowblower. It has a 252cc engine, I am not sure who the maker of the engine is. Here are the oil recommendations straight from the manual. It doesn't get that cold where I live, usually right after a snowstorm the sun comes out and the temperature is in the 40's. I have a quart of Pennzoil Yellow Bottle 10W-30 to use as top off oil while the engine is breaking in. When it is ready for the first change I have a jug of Mobil 1 5w-30 and will continue with that viscosity and in a full synthetic oil for as long as I own the machine.
The so called "expert" in the original post is full of baloney.

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Mobil 1 10-40 in all of my outdoor equipment and two generators and never any problems they get changed on hours or yearly what ever comes first.
 
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My KIA uses 3.5 quarts at an oil change. I save the 1/2 quart. When I get a full quart left over, time to do the Lawn mower. Synthetic oil / blend every year. I bought a Lowes lawnmower (forget the brand) that had a Honda engine on it. 10 years old now. Still runs great (though I need to clean the carburetor.) I'm not sure I buy into someone saying I can't use synthetic oil in it. Ironically, my dad take the used oil in my moms Audi and dumps that in his old lawnmower he uses around the house (they have 80 acres, so just around the house area) and I'm not sure how long that's been running. close to 15 years probably. Someone above said the only thing that matters is it HAS oil in it. I think they're right.
 

ZeeOSix

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The old Honda HR21 L-head engines did in-fact have an oil pump at the bottom of the camshaft and worked the same way as Tecumseh's lubrication system did. I never really understood this given the fact that the upper crankshaft bearing was a ball bearing. On the newer OHV engines Honda did away with the oil pump. An oil slinger was incorporated into the governor gear.
Oil pumps are used to supply oil volume, which ball bearings also need for proper lubrication. Oil pressure doesn't really keep moving parts separated, it's the oil viscosity that does that. Oil pressure is just a measure of how much force it takes to move an oil volume through a path of resistance to supply that oil volume.
 
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Wandering off the OP's subject, but about a dozen years ago, my mom bought a lawn mower from a farm chain store. The salesman swore to her up and down that you MUST use non-detergent in her new lawn mower. If she didn't, HER WARRANTY WOULD BE VOID was what he brainwashed into her head. She purchased some non-detergent oil for her next oil change.
She then thought I was missing a few marbles when she told me that I would being non-detergent oil when I changed oil in her mower for the first time. I quietly opened up the operator's manual and pointed out what the factory said her lawn mower needed. She got quiet after that and took the oil back the next time she went into that store. I just wonder how many other customers used non-detergent oil for the life of their mower?
I ran the snot out of a briggs go kart for 7 years and never changed the oil and only used non detergent.
Never blew it up even reaching back and flipping the governor with my thumb for extended periods.
 

350Rocket

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Through my entire adult life I have fed nothing but Ace Hardware conventional oil to my mowers and have never had a problem. Runs fine.
How long have you kept them? I have one that is 41 years old so far. I would still be using my 41 year old push mower also if I hadn't bent the crankshaft on a huge hidden bolt. I'm 38 so hopefully I have a lot of years left with no plans to replace my equipment.
 
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6 pages about a myth. Though designed for 30w ND they will run forever on anything provided there is enough of it. Stories about exotic oils for one off uses are just fine except they miss the point that tolerances closer than job demands is a waste. :cool:
 
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