Oil Drain Question 21HP Briggs Twin

Changed the oil today in my Briggs Twin. Really hate the drain set-up on this engine. This thing is a disaster waiting to happen. A plastic tube that twists a 1/4 turn to drain the oil, covered with a plastic cap. Click on the thumbnail image for a larger picture:



Model 407577 type 0292-E code 04315-YG
The Briggs engine parts manual doesn't show this item, but the MTD manual does. MTD number is 751-3140, while the small drain plug that Briggs shows would be a 691680. What I need to know is: What size and type of thread is the drain hole that is in the side of the block? I want to replace this hunk of plastic junk with a long brass nipple and cap. Thanks

 

I thought the same thing as you when I first saw these drains, but I haven't seen one fail yet after years of use. I've grown to like them. If you choose to replace it, it's just NPT, 7/16" I think.

 

Actually, this should be a 1/4" pipe thread.

 

While the MTD drain looks good in theory, mine leaks oil out the side slots when opened, making just as big a mess as a simple drain plug would have. So it will be tossed into the weeds as soon as I get to the hardware store. I am going to buy 1/4" pipe fittings and try that, since no one around here has ever stocked 7/16" pipe fittings.

 

1/4" is correct. I'd tell you what I was thinking when I said 7/16", but it would sound even sillier than the original mistake .

 

Well, disaster averted! I bought my 1/4" parts and prepared to replace the factory drain. I searched and searched for a wrench that would fit in the narrow area at the base of the engine. No luck. So I started to close the drain to refill the engine with oil until I can find the right tool. I notice the main body of the drain moves as I try to twist the plastic parts shut! The drain was not even finger tight. Anyway, I managed to get a real drain set up installed so no more oil running under the motor and dripping down on the belts and deck. Just FYI, the drain hole turned out to be 3/8" pipe thread. I had a reducer bushing in the box of old plumbing parts I keep around just in case.

 

Well shoot, I guess we don't know our pipe sizes, huh? That's ok, we're not the plumbing forum, haha . Glad you got it fixed.