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Changing oil in Briggs & Stratton powered Lawnmowers

13593 Views 10 Replies 6 Participants Last post by  Brad
Hello everyone,

Okay, I've had this question in my mind for a looooong time (ever since a saleperson told me to turn the mower on it's side to drain the oil). I have two walk behind mowers I use on a regular basis - one for the lawn and one for weed control. The lawnmower is an older (~12 years old) MTD Yard Machine with a Briggs & Stratton 5 HP engine. The weedmower is an older (~8 years old) Murry with a Briggs & Stratton 4.5 HP engine. My question is: In the Briggs & Stratton Operating and Maintenance Instruction manual for both machines why do they show tipping the engine on its side to drain the oil from the oil fill hole when there's a drain plug in the bottom of the engine itself? Is this because some B&S engines don't have the oil drain plug in the bottom? I've not owned a piece of power equipment that didn't have an oil drain plug. Be somewhat difficult to tip a riding lawnmower over on its side to drain the oil wouldn't it?
Bird Font Parallel Rectangle Illustration

Yes, I see where is states "Note: Top oil drain is recommended method, ...", but why. Is there a reason this is the recommended method? Any Briggs & Stratton gurus that may know the answer to this? Just curious.
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Hi kdursus

Those instructions were added over a decade ago at the request of the mower manufactures Toro was one of them. It was because many walk-behind mowers have some sort of drive belt or mulching baffles that interfere with draining oil from the bottom. To be honest many folks have a hard time finding and removing that bottom drain plug on a grass clogged deck.
I also wonder if you get a better draining by turning the mower on its side. If you have the mower a little bit out of level when using the bottom plug (which is the method I always use, too) you would have some old oil remaining, whereas the tipping method seems to have the oil all running into a bit of a divot on the block where it will get a better drain.

I think dgktech is right, also, about not everyone having the correct tools to get the plug out of the bottom. A lot of those bottom plugs are plastic, too,

I would suspect most riding mowers have a side plug for draining.
draining oil issues

Tipping Techumseh and Briggs engines on their sides seems to be the best method for draining the motor oil, even though they provide drain plugs in the bottom. My Honda gives no other choice than to tip the mower on it's side. At least the drain/fill is on the correct side for this, as the carb is on the other side.

My Mclane rotary (yes, rotary) mower with a Kawasaki engine has its oil fill opening on the same side as the fuel system. The oil drain provided by Kawasaki is located directly below the filler tube, but the oil would spill onto the deck with no drain hole provided in the deck. In addition, Mclane chose to use a transmission like that on Snapper walk-behind mowers, making oil drain access difficult with the gearbox looming over that corner of the mower.:confused:

I used to remove the air filter and tip the mower to drain the oil, then wipe up the oily mess in the breather before reinstalling the air filter, and after that, while holding my nose, start the engine and let the oil burn off for a few minutes.:eek:

I now use the LiquiVac oil changer system. LiquiVac .Not only is it easier, it reduces spillage and eliminates that awful smoke :). I am more likley to change my oil now!
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I don't know, maybe I'm just thinking and clinging to old school practices. :eek:

But even if you warm up the engine first I have this vision of gunk and metal shavings laying on the bottom of the pan not being pulled out by vacuum and getting in the top end of the engine by tipping it over.
Thanks guys for the input. I've not had a hard time draining the oil from my mowers through the block drain plug thus far. I just thought there was some definitive reason why B&S wanted the owner to drain the oil from the top oil fill.

dgktech - That sure sounds like a plausible reason for the instructions in the B&S manual.

LawnRanger - That LiquiVac is an interesting piece of equipment. I've not seen one of those before.

Anyway, I thought it odd when a salesperson told me to turn my mower over to drain the oil. I just laughed on the way home only to find he was right according to the B&S manual. Every time I change the oil in my mowers I think about that salesperson telling me to turn my mower on its side and chuckle a little.
Usually there is a drain plug on the bottom, but on some self propelled mowers like Toros there is no choice but to turn the mower on it's side or upside down over a bucket in some cases. This is incredibly annoying and I hate servicing mowers like that. Imagine having to hold a big, heavy, self propelled Toro over a bucket for a minute or two.
Don't you tip a mower on it's side to access the drain plug? Go ahead and drain the oil while you're searching for a scraper and wrag to expose the plug.
Don't you tip a mower on it's side to access the drain plug? Go ahead and drain the oil while you're searching for a scraper and wrag to expose the plug.
I put the mower on sawhorses and change the oil like a car usually. Prevents gas from going everywhere and the valve case filling with oil.
I put the mower on sawhorses and change the oil like a car usually. Prevents gas from going everywhere and the valve case filling with oil.
Ditto for me except I have a big old porcelin coated crisper drawer I use to catch the oil. I tip it back just far enough to pull the blade and plug by feel, then lower the mower right on top of the pan. I've also done it using cement block.
My son-in-law actually showed me how he uses car stands. Put a couple in the front, a box or crate in the back, and your in business. Gets it about 18 inches off the ground so you can get under the deck to access the plug.
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