How to Change the Oil in a Push Lawnmower (Example: Craftsman, Murray, Briggs & Stratton Engines)
Regular lawnmower maintenance is essential to ensure your lawnmower stays in top running condition. You should perform complete maintenance on your mower at least once per cutting season to maximize the mower’s life, and to ensure your grass is cut perfectly every time.
This article is one in a series of maintenance articles that provide complete coverage of lawnmower care. While not the most glamorous of topics, its a job many of us put off far too long. Want to learn more about mower maintenance? We’ll also teach you how to sharpen a lawnmower blade using a grinder, how to replace a mower’s air filter, and how to check and/or replace a lawnmower spark plug.
We’ll be performing maintenance on two mowers: a Murray with a 4.5 horsepower (HP) Briggs and Stratton engine, and a Craftsman self-propelled push mower with a 6.5 HP B&S engine.
Note that this tutorial is for general information only and isn’t a replacement for the maintenance instructions included in the mower. You should always follow those instructions to maintain your mower properly.
Finally, lawnmowers aren’t the only thing in your garage or shed that should be maintained this way. Any gas powered yard equipment, like pressure washers, chipper shredders, and string trimmers require regular maintenance to keep them running smooth. Most of the principals in this series will apply to all of these types of equipment.
Changing the Oil in a Push Lawnmower
Changing the oil in any gas powered 4-cycle engine ensures the engine stays well lubricated. This keeps the cylinder and piston moving freely against once another, and ensures that scarring doesn’t occur on either, increasing the life of the engine. Changing the oil also offers more immediate benefits: it reduces overall gas consumption, and allows the engine to burn more efficiently, which is better for the environment.
Step 1: Determine whether the engine has an oil drain plug, or if the oil must be drained by turning the mower over. Most push mowers have no drain plug and will need to be turned over to empty the oil.
Step 2:If the mower has a drain plug, unscrew the plug and let the oil drain into a funnel down into a pan. If the mower has no drain plug, unscrew the oil cap, and tip the mower away from the side that the air filter is on. This reduces the chances of the air filter being drenched in oil, which can occur on some engines.
Allow the oil to drain for 45-60 seconds, or until very little is flowing out of the mower. A typical oil change will drain about 3/4 of the oil in the mower. The remaining 1/4 will remain inside the engine, clinging to internal parts.
Step 3: Identify the right oil for your engine. In some cases, the engine will have the oil type listed on a tag on the engine. The maintenance manual will always include the right type of oil to use. Many 4-cycle, small Briggs and Stratton engines take SAE 30 4-cycle Small Engine Oil available at home improvement and auto supplies stores everywhere.
Step 4: FIll the oil resevoir with oil. Be sure to fill only until the dipstick registers “full.” If you overfill, the lawnmower will billow white smoke as the excess oil is burned off during combustion. An engine that is slightly overfilled will exhibit this behavior going up and down hills. Note in the picture below that the top of the Craftsman dipstick indicates a 20oz. capacity; however, this is an “empty” capacity, not a “change capacity.” In this case, we started by adding 10oz., then checking the dipstick every 2-3 oz. until it registered full.
Step 5: Perform the remainder of your maintenance, or start the mower if you are done with maintenance. The mower should be running smooth (or at least smoother than it was running). If the mower isn’t running smooth, check these steps and ensure you’ve done everything correctly. Changing the oil a second time likely won’t solve the problem unless you’ve made a mistake. You’ll notice if you check the oil again that it has turned brown. This is because the new oil and old oil have mixed together. This is OK and is not indicative of a bad change.
What do you think? How often do you change your lawnmower’s oil? Are you due for a change and putting it off?
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5 Responses to How to Change the Oil in a Push Lawnmower (Example: Craftsman, Murray, Briggs & Stratton Engines)
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June 26th, 2009 2:10 pm
where is the drain plug
August 20th, 2009 10:59 am
Where is the drain pug on a murray briggs & stratton 5.5hp
September 14th, 2009 7:59 pm
the drain plug on a B&S is under the deck and takes a 1/4″ ratchet to remove it. I changed the oil in mine today.
December 2nd, 2009 3:21 am
you dont need no drain plug, them new briggs engines aint got one
December 20th, 2009 7:26 am
I use 15w 40 diesel engine oil on a 5 horsepower lawnmower briggs and strattion engine and ive used 20w 50 and 5w 50 mobil 1 oil and i have never had a problem with it when i did use sae 30w i use to go through 10% of oil in the sump and when i use the diesel engine oil in a side valve engine i can see the oil it gets the polutents out and the engine runs alot better then monograde. there is a lawnmower oil that is a 20w 50 and that works great as well and the generater that i use is ohv and i use 15w 40 or 15w 50 or 20w 50 and i have used 5w 50 mobil 1 as well and had no problems with it if you are in a colder area in winter an oil that is 5w 30 lawnmower engines love it and i had a 4 stroke outboard motor on a boat and it used 5w 30 and it had used mobil 1 5w 50 as well. i went in a taxi once and the owner was driving and i asked him what oil he used in it and he said he uses mobil 1 since the car was new and it had 900,000 km on the clock not a rattle in the engine and still running like new and no rebuild at all and my brother was the same with his taxi and no problems at all and if you use a high quality oil it is less likly there will be any problems with the engines on mowers as well and it should get alot of hours out of the motor and car oil wont hert the motor and i have used on 2 strokes like blowers and wipersnipers and mowers high proformance 2 stroke motor bike oil