Here's Your Problem. (19hp Kohler Courage)

[bertsmobile1]

The main reason it happens is the engine is not perfectly balanced and with viberations from the engine and from rough terrain causing bolts to loosen up which causes a more unbalance resulting in the crankshaft counter weight to fly out and hit the block causing major damage and failure. Although I have seen one run with hole in the block. He said mower is making a noise and would like for me to check it out. When he cranked it up to unload it off the trailer it was the last time it ran.

Don't extrapolate your customers problems to cover the entire run of engines.
Most Husqvarnas sold down here are fitted with Courages and very few of them have problems with the bolts loosening.
As for balancing, most are balanced very well, far better than the equivalent Inteks so it will be a 3rd , 4th or higher resonance that is causing the problems.

 

[Luffydog]

The new kohler engine has 2 in it now. Their reason is for quieter but the main is for the balance.

 

[JonnyBlaze]

Picked up another Toro Timecutter with a Courage. This one runs great but has the typical hairline crack. See pics. What can I expect to pay to have this welded or should I just use JB Weld or similar?

 

[bertsmobile1]

Go about 1/8" to 1/4" past the end of the crack and drill a 1/8" hole
This helps to arrest the crack getting bigger.
If you wash the crack really well, JB Weld will fill the crack reasonably well.
Just make sure the bolts on the cover plate are kept tight.
The crank will start weeping after a while, but I have managed to keep a couple of these owned by non - profit / charity clubs running like this.
Also check the oil EVERY time you use the mower.

OTOH I can now weld the cases , with oxy using a DHC 2000 low pressure gun and fine filler rod.
Electric welding does not work as well as you have to get the crack surgically clean & dry in order for the weld to work.

Unless you have a friend who welds, or the gear yourself, a short block will be a better and most likely cheaper if you want a permenent fix.
Products like Lumiweld and similar alloy "welding" rods ( they are actually solders ) can also do a reasonable fill if the crack is really really clean.
But again this is not structural and has little more strength than the JB weld but at least it will not leak.

 

[JonnyBlaze]

Go about 1/8" to 1/4" past the end of the crack and drill a 1/8" hole
This helps to arrest the crack getting bigger.
If you wash the crack really well, JB Weld will fill the crack reasonably well.
Just make sure the bolts on the cover plate are kept tight.
The crank will start weeping after a while, but I have managed to keep a couple of these owned by non - profit / charity clubs running like this.
Also check the oil EVERY time you use the mower.

OTOH I can now weld the cases , with oxy using a DHC 2000 low pressure gun and fine filler rod.
Electric welding does not work as well as you have to get the crack surgically clean & dry in order for the weld to work.

Unless you have a friend who welds, or the gear yourself, a short block will be a better and most likely cheaper if you want a permenent fix.
Products like Lumiweld and similar alloy "welding" rods ( they are actually solders ) can also do a reasonable fill if the crack is really really clean.
But again this is not structural and has little more strength than the JB weld but at least it will not leak.

What keeps the crack from going around the hole?

 

[bertsmobile1]

The crack is longer than what you can see.
The root will be around 1/8" in front of what you see.
Cracks are like water & electricity, they take the easiest path and the hole is an easy path for them to go into but hard for them to leave.
Check the top plate carefully, if the bolt holes are flogged oval, replace the top plate, I forgot to put that in the reply.
If there is no movement then there is no energy to drive the crack growth

 

[JonnyBlaze]

The crack is longer than what you can see.
The root will be around 1/8" in front of what you see.
Cracks are like water & electricity, they take the easiest path and the hole is an easy path for them to go into but hard for them to leave.
Check the top plate carefully, if the bolt holes are flogged oval, replace the top plate, I forgot to put that in the reply.
If there is no movement then there is no energy to drive the crack growth

That makes sense. I was always told to drill right at the bottom of the crack but I will do what you recommend. Thanks.