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

350Rocket

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Been running synthetic in my Honda GCV160 lawnmower for 15 years. It still runs like a top and oil drains clean at the end of the season.

The "use conventional for break-in" talk is mostly because it is less expensive. Do multiple changes during initial break-in with inexpensive conventional oil to get the wear materials (glitter) flushed out. Then fill the crankcase with whatever you want for the regular oil change intervals.
That's the only time I use conventional is if I'm running it a very short amount of time to rinse out, because of fuel dilution or whatever reason.
 
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That's the only time I use conventional is if I'm running it a very short amount of time to rinse out, because of fuel dilution or whatever reason.
I could be wrong, but I don’t think synthetic helps with fuel dilution. Going up a grade certainly would though.
 

350Rocket

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I could be wrong, but I don’t think synthetic helps with fuel dilution. Going up a grade certainly would though.
I just mean I was using extremely cheap conventional oil to rinse out, as one would if they had coolant contamination of the oil.
 

pbm

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I bought a new Craftsman riding mower with a 17hp B&S 'Intek' motor in 2007. For years I used 10w30 Amoco 'Ultimate' full synthetic. I'm sure it was PAO based since it was SG rated and made in 1993 before the Group III wave. Granted it only gets used 5 months a year (maybe 50 hours annually) but it doesn't use oil and still runs like new. PS: I change the 48oz sump and filter at the end of each season ....I've been running oil filters left over from my 2.0 Ford Zetec (Motorcraft 2005 sized).
 
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I was working for a Dodge dealer when Chrysler began running synthetic & for quite some time were told by experts & engineers not to switch to synthetic on older or any high mileage vehicle. Not to ever mix synthetic with conventional or different weights. Man I've worked parts & services for Mercedes, Cadillac, Chrysler, GM.. They told us that for liability purposes only. Personally, unless it was on commercial equipment, I wouldn't run it. For personal use conventional oil rarely gets a chance to break down. You need to change it every every season regardless. Unless you're mowing over 3 thousand miles every 3 months. Lol

Some people said it already. As long as it has motor oil. If synthetic puts your mind at ease, I ain't mad at cha. Lol

I follow the manufacturer on viscosity & that's it. Manufacturers will tell you to run an oil type & brand because they're trying not to get stuck with a huge order someone got a kickback on. Once it gone, it's back to recommending jusr brand.
 
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I was working for a Dodge dealer when Chrysler began running synthetic & for quite some time were told by experts & engineers not to switch to synthetic on older or any high mileage vehicle. Not to ever mix synthetic with conventional or different weights. Man I've worked parts & services for Mercedes, Cadillac, Chrysler, GM.. They told us that for liability purposes only. Personally, unless it was on commercial equipment, I wouldn't run it. For personal use conventional oil rarely gets a chance to break down. You need to change it every every season regardless. Unless you're mowing over 3 thousand miles every 3 months. Lol

Some people said it already. As long as it has motor oil. If synthetic puts your mind at ease, I ain't mad at cha. Lol

I follow the manufacturer on viscosity & that's it. Manufacturers will tell you to run an oil type & brand because they're trying not to get stuck with a huge order someone got a kickback on. Once it gone, it's back to recommending jusr brand.
So hours don't matter?
 
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For what it is worth, Briggs & Stratton still recommends SAE 30 Detergent Motor Oil (SJ or better) above 40°F for all of their engines, including the newer "No Oil Change Ever" engines. If a multi-weight oil is used, you MUST use a synthetic motor oil and check it's level before every use.
 
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If a multi-weight oil is used, you MUST use a synthetic motor oil and check it's level before every use.
That's pretty excessive. Every couple of hours is fine. My flathead only uses a couple of ounces between oil changes both with SAE 30 and 10w30 synthetic.
 
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fwiw i have quaker state full synthetic 5w30 in my lawn mower. just the leftovers from whats left in the jugs/bottles after oil changes. i dont have a clue what kind its supposed to have but its working fine. ive always used this oil and its been running for years.
 

350Rocket

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That's pretty excessive. Every couple of hours is fine. My flathead only uses a couple of ounces between oil changes both with SAE 30 and 10w30 synthetic.
I check every use on newly acquired equipment. Once I see it can go many hours of use without burning oil I relax my oil level checks to every few uses. I just bought a 1979 snowblower a few months ago...oil condition looked really good which was a good sign, but I changed it when I got it anyway since I didn't know the history. Since I changed the oil (with Mobil 1 0w40) it has stayed right at the full and relatively clean for probably 7-10 hours of somewhat heavy snowblowing. It will probably be a once a year oil change now as are my 2 lawn tractors and push mower. Amazingly none of them have used any oil in a year of use and are staying clean looking so I will just do a 1 year oil change on each.
 

350Rocket

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fwiw i have quaker state full synthetic 5w30 in my lawn mower. just the leftovers from whats left in the jugs/bottles after oil changes. i dont have a clue what kind its supposed to have but its working fine. ive always used this oil and its been running for years.
Nothing wrong with full synthetic 5w30 in them. There might be better choices but the difference is probably negligible and its easy to stock 5w30 synthetic for everything. I've used it in all my outdoor power equipment at some point in time when that's all I had, as well as in my 1976 Oldsmobile 350.
 
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I check every use on newly acquired equipment. Once I see it can go many hours of use without burning oil I relax my oil level checks to every few uses. I just bought a 1979 snowblower a few months ago...oil condition looked really good which was a good sign, but I changed it when I got it anyway since I didn't know the history. Since I changed the oil (with Mobil 1 0w40) it has stayed right at the full and relatively clean for probably 7-10 hours of somewhat heavy snowblowing. It will probably be a once a year oil change now as are my 2 lawn tractors and push mower. Amazingly none of them have used any oil in a year of use and are staying clean looking so I will just do a 1 year oil change on each.
I agree on that. However sometimes the oil looks clean on dipstick but dirty when it comes out. I guess it depends on what you define as “clean”
 
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These are not complex engines rare you'll find a full conventional other then HD-30,40.. synthetic blend will cause no harm.
 

350Rocket

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I agree on that. However sometimes the oil looks clean on dipstick but dirty when it comes out. I guess it depends on what you define as “clean”
It always looks darker coming out, and laying in a black drain pan. But if I can clearly see the dipstick through it or my finger I consider it reasonably clean. My girlfriends gdi Hyundai blackens the oil almost immediately after a change and you can't see the dipstick through it. That's normal for gdi but on a PFI engine too dirty imo.
 

twouvakind

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What Honda included with my new mower. Break in oil? I am getting a big no on that!
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Didn't B&S recommend using synthetic 5w-30 in their more recent mower engines?
Yep - my understanding is multi grade oils at the time when B&S was at its peak were loaded full of VIIs and that accelerated oil consumption. Even group III oils need less VII than GI/II oils.

Never used B&S, my small engine experience is with Honda that calls for “any quality automotive oil”. I use Rotella 10W-30 in the equipment I maintain for a local lawn bowling club I’m a part of. For the only small engine I own, a Honda GCV series, I have PP Euro L 5W-30 though in all honesty any 5W-30 will do.
 

350Rocket

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What Honda included with my new mower. Break in oil? I am getting a big no on that!
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If you think you will still be using it in 41 years (the age of the mower I hoped I'd still be using now - 2 years older than me) then use it as break in oil. If you think you'll scrap it in 10-15 years, maybe even 20, don't even think about it.
Right now I have a 41 year old lawn tractor (original Briggs 11hp with a recently replaced head gasket), a 43 year old snowblower (replacement Tecumseh 8hp - unknown age but guessing still well over 30 years old), a 23 year old push mower with quantum Briggs 6hp and a backup 2005 cub cadet lawn tractor that came with the house 23hp Kohler.
I'm 38 years old so I might have a lot of years left to run these things. They hold so little oil and are so easy to change I see no reason not to put high end stuff in and change it frequently. It's not like my truck that takes 6qts plus a filter.
 
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