It is, so whats that tell you about Briggs? They quit making good engines about 10 years ago.
Well, I did research on the Vanguard engines, and they are built by Daihatsu, in Japan... very good engines... many, if not all, think they are better than the same size Honda twins.
Must've had a defect for it to throw a rod in 69 hours, or a loose bolt. It wouldn't be the first time something that is a good engine go bad because of something like that happening. Heck it even happens to the best of the best, even Honda, Nissan, Stihl, Husqvarna, and John Deere. There will always be a few bad apples that get out, no matter who makes it.
This is the first time I've heard of a major problem with a Vanguard, and yes, I have been over a fair bit of the internet on these engines.
Again, must've been a loose bolt, could've been a poorly drilled oil passage, maybe defective oil pump. Or improper break in, there are all kinds of things that could've caused this.
Think Kohler makes the best engines? Most of the time, yes, but the KT17's are some of the only POS that left the factory. Not that many still roar these days, most have been replaced by Honda or Vanguard v twins...
Kohler really ####ed themselves on this engine... even with pressurized lubrication, these engines have been known to break connecting rods, and on the way to breaking the rod, it destroys the crankshaft. Oh, pressures for the oil were only 5 psi for the Series II engines. The Series I had dippers to lubricate the internals, basically meaning the first couple of times you mow a side hill, you would break a rod.
One of our 317's has over 2400 hours on a rebuilt KT17. It still runs good. That guy really knew what he was doing, and stood behind his work. We paid a lot for that tractor ten years ago.
Another 317 we bought is actually newer, and also has been rebuilt. Pops did an oil change on it this spring. Yep, proper oil level and all. I hopped on and started it up, then headed out to start mowing. Knock, knock, knock, knock... yep, it made that dreaded knocking sound... I automatically assumed broken rod, given the history of these engines... and when I tore it apart, this is what I found...
Treepointer, I would call around to Briggs, Daihatsu, etc. and see what they think. They just might give you a new engine, given it happened within the warranty period. Or maybe they would want pics to examine and go from there. You never know until you try.