How to Change the Oil in a Push Lawnmower (Example: Craftsman, Murray, Briggs & Stratton Engines)

July 28, 2008 | by Fred (email) |

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:

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.

craftsman push lawn mower briggs and stratton engine

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.

murray push lawnmowerStep 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.

lawnmower dipstick

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?

53 Responses
  1. Matt Schilling says:

    where is the drain plug

    • pat painter says:

      where (if any) is the oil change plug for a Craftsman Briggs-Stratton model#917 396536

    • Jay Day says:

      Where is the drain plug on a Craftsman 550 series mower? I think it’s under the deck. If I tilt the mower to take out the plug should I drain the gas first?

  2. Bridget says:

    Where is the drain pug on a murray briggs & stratton 5.5hp

  3. MVB says:

    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.

  4. gus says:

    you dont need no drain plug, them new briggs engines aint got one

  5. Sean Zappulla says:

    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

  6. reinhardt says:

    I seem to have trouble starting my briggs and stratton lawn mower,the oil leaks from the exhaust,what could i have done wrong and how can i rectify this?

  7. Fred says:

    Reinhardt, sounds like you might have overfilled the oil. Is the exhaust smoky?

  8. Reinhardt says:

    The exhaust is always smokey..

  9. debi says:

    where do you put the oil in a briggs 4.5 push mower ? i just bought a used one and it may be missing the stick ?

  10. Sean says:


    That’s one helluva accent you got there Sir. I can hear it through your keyboard. I had to comment on that. Thanks for the tip!

  11. Kim says:

    I just purchased a 5.0 hp 20″ Briggs & Stratton Push Lawn Mower . Do I mix the oil and gas together.

  12. kate says:

    @ Kim:
    Do NOT mix oil and gas for your lawn mower! It will be a disaster. I filled mine with what I thought was plain gas, but my husband had mixed oil with it for the weedeater. The lawn mower billowed out white smoke and stunk up the whole neighborhood. He lables the gas cans now!

  13. Miguel Rodriguez says:

    I need to change the engine oil to my Craftsman Briggs & Stratton 6.25 Hp front gear drive. The machine have the drain plung underneath but there is a plastic cover for the belt that blocks the drain plug. I pull out the blade but I can’t get off the plastic cover. How I suppose to change the oil? Thanks in advance for your help.

  14. Steve Roth says:

    I have a used Craftsman 6.75 HP mower I bought from a friend. Needless to say, no maual. I”m not sure what kind of oil I can use in it (if regular mower oil isn’t available). He says regular automobile oil. I don’t trust his judgement.

  15. tyron says:

    you change oil on a 4.6 & 6.5 is it done the same way on a 5.50 Silver Edition Brigg &Straton 21 inch cut ?

  16. Vicster says:

    I have a Craftsman front propelled gas mower. I used it about a month ago and it kinda “sputtered” a few times while mowing (I have 3 very large sections of grass to mow). I went to use it the other day and it won’t start. It has gas and oil. Could it be that just the sparkplug needs replacing? The mower won’t fit in either of our cars to get it to the shop (not that I want to get ripped off by them) but if I can get it running by changing the plug, that would be great! The lawns look terrible and my landlord lives right next door

  17. Dan Lynch says:

    I have a Craftsman 6.5, self propelled lawnmower.
    Either side discharge or rear baging.
    Where is the drain plug?

  18. Fred says:

    Without seeing your particular lawnmower, I can’t be sure. Odds are that it has no drain plug and that you’ll need to turn it over in order to empty the oil.

  19. roger says:

    I have a b&s 6.75 ohv pressure washer.It has no dipstick,so is the proper oil level up to where it runs out of the oil plug hole or just up to the bottom of the threads?Thank you.

  20. Fred says:

    Roger, sorry, that’s one we can’t help you with.

  21. jessie says:

    how much oil do u put in a poulan pro just got it with no oil in it

    • Ethan says:

      Hi Jessie, I’ve never worked on a Poulan Pro. Did it come with a manual? If not, you can download one here: The manual will indicated what type of oil and how much. Additionally, the mower probably has a dipstick with a “Full” line that helps you determine when to add oil. Hope this helps.

  22. carol strickler says:

    I have a Briggs and Stratton…6.50 and need to add oil…what kind does it take? its a key start…

  23. carol strickler says:

    I cannot find my booklet on it!

  24. Keppie says:

    I have a Craftsman push mower (circa 2003) with a 6.5 hp B&S engine. My question is regarding the setting the correct position of the dipstick when checking the oil level.

    When inserting the dipstick in the filler tube, it typically stops at the point when the mating surface of the dipstick touchs the upper flange of the oil filler tube. (Position 1)

    To lock the dipstick for normal operation, it is rotated slowly until the dipstick hits the locking slots on the flange, it is pushed down approx 1/4″, and rotated to the lock position. (Position 2)

    Which position (1 or 2) of the dipstick is the correct position to accurately check the level of the oil?


    • Fred says:

      Keppie, REALLY tough question and it shouldn’t be. I can tell you that I usually do lock the dipstick in place, then unlock it and use that reading. You’re talking about 1/8 of an inch usually, so I don’t know that it’s that dramatic of an effect. I’ve never had a problem using this method.

  25. Adam Scott says:

    What type of oil do I put in a Murray 22 lawnmower with a Briggs and Stratton engine?

  26. jodi dean says:

    I am trying to get my mower in shape. I can’t seem to get the oil cap off the Craftsman self propelled push mower. What can I do? It turns and I can hear clicks but it won’t lift off

  27. Brady says:

    Don’t forget that depending on the engine it might be best to run out the gas first too to keep it from leaking.

  28. tyisha gamble says:

    my son turned the lawnmower over to empty some of the grass that was underneath ever since the mower has been smoking and putting like we have bad gas please help it a brand new mower not sure what he could of done but as he cutes the grass it sparks and blows out smoke!!!!!!!!

    • Fred says:

      Probably got oil into the air filter. Change the air filter first, let it sit for a while, and then restart after a few hours. If there’s too much oil (overfilled), you will need to drain out the oil to fix it.

  29. Mike says:

    doesn’t a briggs and stratton motor for lawn mowers( push ) have some sort of oil filtering unit on them to look at when doingn oil change?

  30. samantha says:

    i got a craftman briggs and stratton silver series, 5.50 lawnmower. i got it last year. i lost the booklet that came with it. what kind of oil does it take? i think it takes reg car oil but want to be sure

    • Fred says:

      Probably takes traditional 4 cycle oil. You can find stuff formulated for lawn mowers at Sears, and they should also be able to answer your question on this engine.

  31. Keith says:

    I have a Craftsman 190CC 22″ that started blowing smoke, sputtering, and finally dying, so I knew that I had overfilled the oil. I drained it and replaced with what seems to be the right amount of oil. It started once after that but I let it stop (to take care of the oil pan) but when I returned it wouldn’t start at all. I’ve tried for the last 20 minutes to start it with no luck. Any ideas? Do I need to let it sit for a while?
    Thank you!

  32. Nick says:

    I have a b&s 625 went to cut grass, it started popping and suddenly died. Thought I had water in the gas, changed it and checked carburetor still doesnt start. Can u help?

  33. MIKE S says:


  34. Lawrence Hayes says:

    Thank for super info

  35. Karen says:

    I hit a rock bent blade I put a new blade on it backfires when I try to start it timing is thrown off from the rock how do I fix the timing

    • Denny says:

      You need to take the top off the motor. The finned flywheel must be pulled off the top of the crankshaft but first starting spring and cable. The crank has a slot type shear pin most look like a half moon or flat key that fits the slot. Take your old busted one so you get the correct size. Reassemble. You are right the timing is off as the pin sheared and the magnets inside the fly wheel are shifted.

  36. Rob Boucher says:

    Have older 21inch self propelled B&S with carb 790821 if manual is correct. Can someone provide pic of proper hanging angle for this all plastic tab float? After playing with tabs and replacing needle seat this fool reads these all plastic tabs should not be tampered with. Emulsion tube clear,1/4 inch nut holes clear and new primer gasket but starves for fuel HELP

    • Rob Boucher says:

      I should also mention have to start by removing filter cover and spraying fuel into throat of carb past emulsion tube .Usually starts on second /third pull and after 20 seconds starts drawing fuel and runs perfect.Whats wrong please?

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