Briggs Leaking Oil

[Scrubcadet10]

I tell you what you're luckier than me. Almost every mounting bolt on that type of engine, to the deck, i've encountered even after soaking in penetrating oil, either snaps off in the engine or rounds the head off. i usually end up drilling them out and going back with 5/16 grade 8 bolts and nuts.

 

[Mr-Mom]

Well, I don't have it off yet. But I'll take your advise and get the bolts soaking right away. I won't get a chance to work on it until next week. By then it should be loosened up, if the bolts are corroded. This machine is not that old and in pretty good condition. Chances are the bolts are not too bad.

 

[Mr-Mom]

I thought I'd confirm my theory that the oil is coming from the seal between the block and the oil pan. I started the machine (that's another issue - it does not start well now) to get it good and warm and then set it on a milk crate with the nose down to see if I could spot the leak. This didn't work well. After two hours of sitting, there was no appreciable leak. I then started the machine again and worked it hard mulching up some deep leaves. In short order I could see oil accumulating on the mower deck below the muffler. Attached is the best photo of this I was able to get. The visible bolt head is the lower bolt of the oil breather. You are looking in from the side towards the front, right under the cylinder cooling fins. My guess is that the gasket is leaking in this area, though it only seems to do so if you work the machine hard. If you just let it idle, it never starts to leak. Does that make any sense?

 

[tom3]

Has that sump base been repaired at some point? JB Weld maybe? Not sure from the picture but something looks odd there.

 

[Scrubcadet10]

Has that sump base been repaired at some point? JB Weld maybe? Not sure from the picture but something looks odd there.

if you mean to the right of the bolt head, i think that's the edge of the valve cover/breather assembly. looks pitted

 

[Mr-Mom]

Hard to say about repairs. I got the thing when it was being tossed out by its original owner at the local transfer station maybe four years ago. The guy said it would not run and he couldn't fix it. The issue was a clogged main jet and I had it running in less than an hour. I'm pretty certain that this was a guy who was not going to take on a replacement of the sump gasket or even do a bondo job to some leak.

I'm not sure exactly when I first noticed the oil leaking. I used it hard one day (I mow the woods with it) and it started to knock badly. I shut it down and checked the oil - none on the stick and it took a bunch. Since then, I've regularly had to top it up. The valve cover/breather is brand new and I sealed it with Permatex in addition to a new gasket. I'm certain that is not the source of the leak though the oil appears right under there. Take a look a this video

, about 4:20 in. I think this is my issue. the sump gasket has failed in the area under the cylinder. Now I'm wondering, should I fix it with a new gasket or use a good gasket sealer? Clearly the stock gasket, which is just paper, is not so good.

 

[Scrubcadet10]

You can either go back with a new gasket, or gasket maker, I prefer Permatex Ultra Black sealer. Clean both surfaces really well, apply it to one of the surfaces. And just snug the sump bolts up. Wait 24hrs, then torque the bolts.
the torque spec for the sump is 90 Inch pounds

 

[Mr-Mom]

Sounds like a plan. I'll probably get on it next week. Have a happy Thanksgiving. I'm being grateful for good help - thank you.

 

[bertsmobile1]

BE careful doing that
The gasket sets the end float of the crankshaft
So you can end up with it flopping around like a dunny door in the wind or being as tight as a fishes bum

 

[Scrubcadet10]

The 12 series. Vertical use a shim for end play