It seems that at least one of them needs repairs of some sort when first use in the spring. I think I had bad gas last fall they all gave me problems but with new gas two are fine now. The oldest of them needs a new carb which I have two on hand.
I've learned a few things over the years about these...
After taking the back belt/drive cover off to fix whatever doesn't work just leave the dang thing off to easily remove sticks and pine cones, etc that jamb up the drive belt.
Don't wash them down with water and put them away. The bowl shape in the drive system idler pulleys will let water sit there and rust/seize the bearing.
My man.... I thought I was the only one with his and hers push mowers. Soooo romantic. Wife and I do a little pushing if you know what I mean on Saturday's.
@slomo Your signature reminded me to check and clean out the cooling fins on my B&S Intek engine. The narrow cooling shroud on the side/under of the cylinder always gets totally clogged with clippings especially when I use the mower to mulch leaves in the fall. 1 of 3 done so far with before/after pics...