Craftsman LT 4500 26HP Briggs Stratton Intek Both Pistons not moving

[DinosaurMike]

Can you access both ends of the crank? Valves move because you are turning the crank at the end with the drive gear for the cam. I would guess that the other end of the crank does not turn when you turn the end that you are turning. I know nothing about lawn mower engines, but that is my theory after looking at the parts breakdown.
It also looks like there is only one throw on the crank. Do both pistons move up and down together?

 

[Forest#2]

Is the engine still on the mower?
Is the starter spinning the flywheel? (You seem to indicate that you can turn the flywheel?)
Does the PTO end of the crank turn when the flywheel turns? Was the engine running when it happened or did you just go to start the engine and failure?

Reason I ask is the crankshaft either broke above the first rod and below the flywheel or the flywheel came loose???

I've never seen either but as the other guys indicate it needs to be checked further.
It needs an autopsy and a colonoscopy.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[Air4Dave]

The only issue with that is the valves are moving, and since the camshaft is driven off the pto end of the crankshaft, the crank from the flywheel to at least the timing gear would have to be intact which would include the rod bearing area of the crankshaft.

I can see that happening. This appears - per the above discussions - that this is not an isolated issue! One that B&S should certainly be aware of and offer some kind of assistance! It could be an isolated bad batch of crankshafts or, more likely, connecting rods/bearings. Unfortunately, most manufacturers these days don't want to do the ethically correct thing and pay for part of the repairs.

 

[ILENGINE]

I can see that happening. This appears - per the above discussions - that this is not an isolated issue! One that B&S should certainly be aware of and offer some kind of assistance! It could be an isolated bad batch of crankshafts or, more likely, connecting rods/bearings. Unfortunately, most manufacturers these days don't want to do the ethically correct thing and pay for part of the repairs.

There are more questions than answers and since the OP hasn't been here since May 25 we may never get those answers. With a little research I can't find a model LT 4500 but did find a YT 4500 which was made before 2014 so if that is true this engine is at least 10 years old. And the 26 hp engine that they list was the Kohler Courage 26 hp so may not even be a Briggs. So if what I found is true I am not going to blame the issue on a bad batch and crankshafts, or connecting rods/bearings. And I don't know of a single manufacturer of any brand that would pay for repairs or parts on a 10 year old engine.

 

[Air4Dave]

There are more questions than answers and since the OP hasn't been here since May 25 we may never get those answers. With a little research I can't find a model LT 4500 but did find a YT 4500 which was made before 2014 so if that is true this engine is at least 10 years old. And the 26 hp engine that they list was the Kohler Courage 26 hp so may not even be a Briggs. So if what I found is true I am not going to blame the issue on a bad batch and crankshafts, or connecting rods/bearings. And I don't know of a single manufacturer of any brand that would pay for repairs or parts on a 10 year old engine.

Agree! Thanks for looking further into this. I didn't have any idea this engine is that old! I, too, have a T2400 w/the B&S engine but it runs just fine. It's also 10 years old and I just got it from my neighbor in a trade. It wasn't taken care of very well, as far as the blades, seat, lubrication, and steering, but I've replaced and/or fixed it back to good working order. Fortunately, he DID take care of the engine!

 

[bertsmobile1]

I like the way every one starts to jump to conclusions without recommending some simple tests , like turning the engine from the PTO shaft end and seeing if the pistons move
Consider this.
Engine seizes & flywheel spins on taper thus becoming loose
Starter spins flywheel but flywheel is not spinning the crank because the engine is locked up tight as a drum
This will happen if the oil is a bit low and the owner is driving along a slop with the oil pick up on the high side