How to drain oil on B&S 725EX engine?

To get the engine to 'hydrolock' from being tipped on its side/end would take some time UNLESS your rings were pretty well worn out. Hydrolock is the situation where there is liquid in the combustion chamber that prevents the piston from fully traveling to TDC(top dead center) and which may cause physical damage to the connecting rod/piston if the piston is forced to attempt compressing the liquid. It would take a good quantity of oil leaked past the rings into the combustion chamber to prevent the piston getting to TDC. Good quantity being on the order of 1/4 cup of oil, roughly. It could happen, but you'd have to have it sitting for some time to allow the oil to seep past.

One thing to remember is that you want to have the carburetor side 'up' if you tilt your mower to drain the sump. If carburetor side down, you run the risk of flooding the engine with fuel.

tom
 
Hi, Simply place a proper container on the floor and remove the dipstick. Tip the mower on its dipstick side, ensuring the container is in the right place to catch the oil. Let the oil fully drain, simply set it back on its four wheels, and refill with roughly 18 ounces of 10W30 synthetic oil. Let it sit for a few seconds to allow the oil to clear out of the dipstick tube, wipe off the dipstick, and check the oil level. Dispose of oil properly. It is very simple. It will not hydro-lock; it is designed to be changed in that manner. easy-peasy
 
Last edited:
Hi, Simply place a proper container on the floor and remove the dipstick. Tip the mower on its side, ensuring the container is in the right place to catch the oil. Let the oil fully drain, simply set it back on its four wheels, and refill with roughly 18 ounces of 10W30 synthetic oil. Let it sit for a few seconds to allow the oil to clear out of the dipstick tube, and check the oil level. Dispose of oil properly. It is very simple. It will not hydro-lock; it is designed to be changed in that manner. easy-peasy
 
kbowley said:
Hi, Simply place a proper container on the floor and remove the dipstick. Tip the mower on its side, ensuring the container is in the right place to catch the oil. Let the oil fully drain, simply set it back on its four wheels, and refill with roughly 18 ounces of 10W30 synthetic oil. Let it sit for a few seconds to allow the oil to clear out of the dipstick tube, and check the oil level. Dispose of oil properly. It is very simple. It will not hydro-lock; it is designed to be changed in that manner. easy-peasy
Click to expand...
Yes, easy peasy, if one likes to invert their mower over a drain pan and hope to not fumble it. Those pesky mower handles can into play, messing with the inverting action. Wear gloves,too. Inverting the carb and fuel tank can give rise to other issues. I had B&S easy Drain spouts on my drain ports , but removed them due to possible leakage and 'no oil' situations on my side drain engines The suction method is quick and easy, with no mess. Maybe a little mess if one is a bit inept(like me), but you may have that with turning your mower upside down,
(I'd repeat post this, but you get my point)
 
Hi, Simply place a proper container on the floor and remove the dipstick. Tip the mower on its side, ensuring the container is in the right place to catch the oil. Let the oil fully drain, simply set it back on its four wheels, and refill with roughly 18 ounces of 10W30 synthetic oil. Let it sit for a few seconds to allow the oil to clear out of the dipstick tube, and check the oil level. Dispose of oil properly. It is very simple. It will not hydro-lock; it is designed to be changed in that manner. easy-peasy
SamB said:
Yes, easy peasy, if one likes to invert their mower over a drain pan and hope to not fumble it. Those pesky mower handles can into play, messing with the inverting action. Wear gloves,too. Inverting the carb and fuel tank can give rise to other issues. I had B&S easy Drain spouts on my drain ports , but removed them due to possible leakage and 'no oil' situations on my side drain engines The suction method is quick and easy, with no mess. Maybe a little mess if one is a bit inept(like me), but you may have that with turning your mower upside down,
(I'd repeat post this, but you get my point)
Click to expand...
Where did I say invert? Simply tip it on its side. I do it several times a day in my shop. It is VERY easy. There is absolutely no need to purchase a topside sucker unless it's a cheap box store unit without a dipstick. I have an OEMTOOLS oil extractor for those and generators, pressure washers, zero-turns, etc. But he has no need for that. I have only been owning/running an outdoor equipment shop for 20 years, but what do I know?
 
Last edited:
When you own 5 mowers, a top side sucker as you say is a dream. Plus when you tip you can scratch the deck, wheels and handlebar up.
 
Last edited:
My MTD push mower with a B&S engine has a drain on the bottom, but then I bought it new in 1990. I keep it inside out of the weather with annual maintenance, and it starts first or second pull every spring. I think if I hjad a new one with the drain covered, I would remove the engine once to locate the drain, then cut a hole in the deck to access the plug in the future.
 
You must log in or register to reply here.
Back
Top