Motor fine, but the saw blade isn't moving and of course won't cut cut. Am I missing something obvious, or Is there a drive belt that's broken or something similar.

Pull the saw apart and inspect the parts, something is broken that is for sure, only a through inspection will reveal the cause, it is a never before heard problem.

There's a little black button to press to lock the blade so you can loosen the screw. Did it get stuck in the in position? Can you turn the blade by hand (unplugged of course)?
I believe the 718 has a belt drive. Could the belt be broken and be buckled or twisted in its case preventing any movement?
Was it left out in the weather and did you get water in the bearings?

UNPLUG the saw! IF your saw is a direct drive; either the blade is loose or the center of the blade is broken, Or the motor shaft has broke off. IF your saw is BELT DRIVEN, check the belt tension, or belt condition.

I had a similar problem with my TroyBilt 50 inch zero turn mower. Was cutting grass when it stopped going either forward or backward even though it would start and the PTO would move the cutting blades. Turned out the tensioner spring for the belt that drives the motors near the rear wheels had gone missing. Searched the yard where I had cut and moved the machine but couldn't find it. A new one cost me about $7.50. Put the new one on and it worked fine.

there are several rods that support the deck if one is missing it can allow the deck to move in the wrong dirrection

Don't want to state the obvious but is the blade on in the right direction?

From the description it sounds to me like the bolt holding the blade in place isn't tight enough, obviously. If there isn't a button on the saw that stops the blade from rotating when you're changing out the blade. Try this--when tightening down the blade, put it on the saw, then open the guard and rest the blade on a piece of scrap wood to stop if from moving. Then fully tighten down the bolt that holds the blade in place and you should be fine.

Check that the bed of the saw (the flat metal part on the bottom) isn't bent. I've had this sort of thing happen on a jigsaw that needed to be tapped back into square. Check the squareness of the saw with a framing square or a carpenter's square held against the blade and the bed of the saw with the blade guard open. Obviously, make sure the saw is unplugged before doing this.

hi, on your Delta saw shaft has two flanges which one goes in front of the blade and the other behind the blade. These flanges have two flat spots in the center of it which over the shaft, the blade has the same cut out so you need to check your shaft, flanges and blade to make sure they are all locking on the shaft. Do not forget to unplug the saw before you do any work.

Hi
Try these things first.
1) Verify a circuit breaker isn't tripped
2) Advance the timer control dial slowly 360 degrees-
If the washer starts spinning, then we know the motor and drive belt are fine but that there is something wrong with either the timer control dial or the agitator solenoid. Call in a professional for this.
If the washer doesn't budge, then verify that the drive belt(s) is attached and not broken by removing the back panel. If the belt is broken, replace it. If it is loose, then tighten it by loosening up the bolt holding the motor and moving it on its swingarm (much like a car alternator) until there is a 1/2 to 3/4 inch deflection in the belt. Some washers use reversing motors. It's possible the motor works on the spin cycle but not on the wash cycle. If so, call a pro.
3) Visually inspect the lid safety switch- Is it loose or cracked? If so, the washer might work intermittently, stopping at different cycles.
4) Check motor and drive belt- Remove the main access panel (usually in the back). Is the motor spinning, but the drive belt isn't? If so, then you have a drive belt problem. Go here. If the motor isn't spinning, then go here for washer motor troubleshooting.
If none of these tips resolve the problem, then there's probably a more serious problem with either the motor, the transmission or the agitator itself. If this is is the case, call in a pro.
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