My dad has a Briggs & Stratton 4HP 4-cycle lawnmower and he has /never/, I repeat, never changed the oil in it since he's owned it (about 5 years). I went to check the level today and surprise surprise, it was below the low mark and completely black. Anyways, I tried tipping it to change the oil and learned a fun lesson about vented gasoline caps (gas all over the driveway!) so my question is this, how do you all go about changing the oil on a bottom drain lawnmower? It's right above where the blade is. I was thinking of either running it 'til it's out of gas then tipping it to drain it, or perhaps putting it up on two stands and having my dad hold it while I take off the plug so it won't fall on me. The manual wasn't much help, unfortunately. Oh also, I used SAE30 B&S oil from 2002 to top it off, should still be good, but would putting a synthetic 5w-30 in it for him next time make much sense, since he never bothers to check or change the oil? Or just keep using some SAE30? He never operates it in below 40 degree weather and the manual states to use SAE30 between 40-100+ Fahrenheit. It says you can use 5W-30 Synthetic for all temps but to be warned of possible increased consumption... Sorry for the long post! Thanks in advance for any advice, i'm totally new to changing oil on lawnmowers.
B&S 4HP 4-Cycle, Changing Oil
- Thread starter ThirdeYe
- Start date
- Status
If it has a drain plug underneath, as most B&S do, turn the blade so it's out of the way, and loosen the plug, and set the mower up on cement blocks or just on top of a larger round drain pan. Then remove plug. I'd flush with K2 and drain well before adding new oil. Then I'd change it again after a couple of mowings.
My 2¢
My 2¢
Hey 3rdeYe-
Try some 15W40 HDEO from Wallymart or similar for your Dad's B&S.
dwendt44 is correct that there should be a square plug at the bottom of all B&S horizontal engine: 3/8" is the socket size and all you need is a rachet and an extension bar to break free.
Cheers,
Q.
Try some 15W40 HDEO from Wallymart or similar for your Dad's B&S.
dwendt44 is correct that there should be a square plug at the bottom of all B&S horizontal engine: 3/8" is the socket size and all you need is a rachet and an extension bar to break free.
Cheers,
Q.
Top it up with any cheap oil so it's at the correct level then run it out of gas.
As soon as it's out of gas, just tip it over and let it drain. This is the easiest way, no messing with the bottom drain.
As soon as it's out of gas, just tip it over and let it drain. This is the easiest way, no messing with the bottom drain.
If you drain from the bottom ensure the spark plug wire is disconected.
Just curious, what would happen if I didn't undo the spark plug wire? I'm worried I may have messed something up because after topping it off and re-filling it with gas, I noticed my dad struggling to keep the thing running and I'm worried that maybe me tipping it over messed something up (but I didn't actually drain it) then I tipped it back over again after noticing gas spilling out down the driveway and just topped it off instead of changing it.
Last edited:
ThirdeYe,
The reason behind pulling off the spark plug wire is to prevent accidental turning of the engine/blade that would have caused accident. This is a standard safety practice when seriving small gasoline engine (or even large gasoline engine).
As to why your dad was struggling to get it to running, truth is, when you turn over the engine, fuel gets into the cylinder causing it to flood. It would take several pulls to start, some smoking and hesitation to run for a few mins before everything clears itself out and all shall be fine again afterwards.
Cheers,
Q.
The reason behind pulling off the spark plug wire is to prevent accidental turning of the engine/blade that would have caused accident. This is a standard safety practice when seriving small gasoline engine (or even large gasoline engine).
As to why your dad was struggling to get it to running, truth is, when you turn over the engine, fuel gets into the cylinder causing it to flood. It would take several pulls to start, some smoking and hesitation to run for a few mins before everything clears itself out and all shall be fine again afterwards.
Cheers,
Q.
I think I read that something like 30 people are killed every year in North America by walk-behind lawnmowers. Pepper's warning is legit. If you try to push the blade aside to expose the drain plug, the engine could fire and chop off your hand or whatever else is in the way.
If he/you turned it over with the muffler down, the carb probably got a good oiling from the crankcase breather. Disconnect the plug...we know it has a safety bar/brake in place, but cut up hands happen! Tip it as far over as you want if the muffler is up. If the gas runs out, catch it with a tin can or something. Using a ratchet and extension bar, loosen the plug on the bottom. It may take a 3/4 inch socket, but more than likely is just a place to insert the extension bar. Let the oil drain...tip it over at different angles to get all the oil out. Replace the plug...tighten firmly, but there's no need to kill it. Replace the oil with whatever brand SAE HD 30wt oil. Don't ever overfill. If the engine keeps acting up, take the breather off and clean everything thoroughly. Take a digital picture of how the carb linkage is hooked up. Pull the two bolts that hold the tank on. Pull the tank and take the carb loose (5 screws). If the diaphram looks bad (is pulled away from the gasket, take it to the auto parts store and get a new one. O'Reilly's sells them around here for $1.99. Clean everything up and go in reverse. The thin membrane goes against the tank--the gasket against the carb bottom. If you need more help please feel free to ask or drive to Omaha.
Thanks Quest I think that might be what happened. It ran for a few seconds, then it would die, rinse & repeat but I think he eventually got it going and we'll keep an eye on it. I'll take charge of doing the maintenance on it since he apparently doesn't care enough to. He said he's never changed the oil in any of his lawnmowers, ever!
Use a cheap plastic bag as temp seal between gas cap and threads. Very little gas leaks out. Cost less than 2 cents if that - problems solved. I also use a cut down pallet at an slight slope so I can lean over the mower at an ideal angle to drain the last drop out of it. Since it's not a Kawasaki mower with a filter I typically flush once with chepo Super Tech every oil change.
I've been running either Napa Synthetic 15w-50 or Mobil 1 15w-50 in my mowers & tillers. Will probably switch over to Shell Rotella 5w-40 as soon as my stock is gone. Also would be pretty happy with most any of the HDEO 15w-40 oils out there. I also use a tad bit of ZDDP booster such as STP New Car Oil treatment or Valvoline Max Life or Valvoline SYn Power to a make up for diminishing Zinc levels in the oil these days.
I've been running either Napa Synthetic 15w-50 or Mobil 1 15w-50 in my mowers & tillers. Will probably switch over to Shell Rotella 5w-40 as soon as my stock is gone. Also would be pretty happy with most any of the HDEO 15w-40 oils out there. I also use a tad bit of ZDDP booster such as STP New Car Oil treatment or Valvoline Max Life or Valvoline SYn Power to a make up for diminishing Zinc levels in the oil these days.
As far as I know, he's gone through 3 or 4 in the past 15 years. We're starting to have troubles starting this one, but I don't think it has to do with the oil issue. I think it has to do with the fuel priming system.
I should disconnect the spark plug wire from now on, though I must say no trouble as yet.
I tip the mower so the tank goes high (which is usually low as I refuel before mowing). At this point I check to see if the blade needs sharpening/replacement, and if so I remove it. I clean around the plug, either with a spray of carb cleaner or a good blast from the garden hose. With the plug area dry and clean, I position a shallow pan and remove the drain plug. I put the mower back on it's wheels being sure the oil drains in the pan. I usually check to see if the pan I'm using requires me to raise the mower, and if so I adjust the wheels before lugging block around. Even if the mower rests on the pan with it's blade, no big deal. I just make sure the mower is leaning so as to get the most oil out of the case. One may also want to loosen the fill cap to allow for faster draining. I then sharpen the blade if needed, get the fresh oil bottle(s) and a clean cloth to check the level and to rest the fill cap/dip stick on. Draining complete, I tip the mower up again as I did before, I pull aside the pan, clean the drain plug and reinstall. I then reinstall the blade if having removed it previously, and then back on four wheels again. I add and check the level. The used oil gets transfered to the used bulk tank for recycling.
That's kind of the long-winded version of how I change the oil on my push mowers (Toro and a free Briggs unit).
Take care
I tip the mower so the tank goes high (which is usually low as I refuel before mowing). At this point I check to see if the blade needs sharpening/replacement, and if so I remove it. I clean around the plug, either with a spray of carb cleaner or a good blast from the garden hose. With the plug area dry and clean, I position a shallow pan and remove the drain plug. I put the mower back on it's wheels being sure the oil drains in the pan. I usually check to see if the pan I'm using requires me to raise the mower, and if so I adjust the wheels before lugging block around. Even if the mower rests on the pan with it's blade, no big deal. I just make sure the mower is leaning so as to get the most oil out of the case. One may also want to loosen the fill cap to allow for faster draining. I then sharpen the blade if needed, get the fresh oil bottle(s) and a clean cloth to check the level and to rest the fill cap/dip stick on. Draining complete, I tip the mower up again as I did before, I pull aside the pan, clean the drain plug and reinstall. I then reinstall the blade if having removed it previously, and then back on four wheels again. I add and check the level. The used oil gets transfered to the used bulk tank for recycling.
That's kind of the long-winded version of how I change the oil on my push mowers (Toro and a free Briggs unit).
Take care
Forgot to add that this year I've started using 15w-40 HDEO, though the Toro gets M1's 15w-50 because it's showing it's years and burns some oil. I could probably rebuild the car as it seems to have the bowl run over in storage, but have instead installed a fuel shut-off. I've also limited it's use for fall and spring bagging, making the most of what utility it has left in it's current state of repair.
Take care.
Take care.
- Status
