My mother bought a craftsman (generic) brand small gas generator, approximatley 7 hp motor-- about 2 years ago. I thought I was going to help her out and drain oil, replace, filter, clean air filter, etc., The problem I am having is that it has a drain plug with the square end, two of them as a matter of act , and how this thing was built I can not get a wrench on it due to restrictions from the frame and how the engine sets. I have never seen anything more mickey mouse in my life-- Nor have I found anything so simple yet seems impossible to remove the drain plug, short of removing it from the frame I really don't know how I can get in leverage on this any ideas-- I need all the help I can get on this simple/impossible drain plug.

 

Buy a socket for square nuts or plugs, I have several I use. They are 8-point sockets available at most hardware stores. Those square plugs are common. Square nuts and bolts are common on older machinery.

 

Depending on the size of the square, you might be able to use an extension bar turned the wrong way around with an adjustable on the other end. On a square head plug, the fit can be pretty loose before it will slip past the corners.

 

I have a high pressure washer that is absolutely impossible to get the drain plug out of because it's 40% covered by the sheetmetal stand the vertical-shaft engine is bolted to. Since the gear pump is bolted to the underside of the sheet metal and direct-coupled to the engine, it would be a terrible job to change the oil using the drain plug (the engineers designing this machine definitely had their heads stuck up someplace where the sun doesn't shine).

Here's what I do. Run the engine to warm up the oil. Shut down, remove the fill plug, and suck the oil out using a battery fill bulb, a turkey baster bulb, or a hydrometer with the float removed. If the fill plug channel is really long, slip a 6" piece of vacuum hose over the bulb snout to extend its reach. You can even tip the engine toward the fill channel to suck out the very last bit of oil, too, and get the "really good stuff" out of it that typically doesn't come out through the drain plug.

And if you suspect there's a lot of sludge in the bottom, once you've sucked the oil out you can "power squirt" some kerosene in and swish it around by rocking the motor back and forth. Then suck it bone dry, just like you removed the oil.

On my lawnmower, the recessed square in the drain plug is 3/8" and I can just use an extension bar to remove it. However, I don't like having to block the mower up so I can get a drain pan under it and then battle all the caked grass that's jammed up in there. I still take the oil out through the fill plug.