I have a 1981 C21ZPRA w/o self-propel. It has a magnesium deck w/rear discharge. I bought it with the rear bag (standard); later I bought a side discharge chute. I don't have the mulching plate, but I never have cared for mulching anyway.

The Mg deck is prone to cracking from rocks and having sticks jam between the blade and deck. The lower chute plate is plastic and after going thru 2 of them I do without. It doesn't make any difference as far as I can tell anyway.

The parts are REALLY expensive, that is, the ones that are still available. I wouldn't give much for one of these mowers even if it runs well and is in good shape (no cracks or significant corrosion of the deck).

When it was new the fuel tank leaked and was replaced under warranty with a revised design.

The CD ignition module failed and was replaced under warranty.

The recoil spring broke and was replaced under warranty.

The rear bag frame broke at a weld and was repaired under warranty.

I bought this mower from Green Hills Lawn Mower in Nashville, Tn. on a discontinued closeout for $300. In 1981 or 2 it listed for over $600. I have definitely gotten my money's worth out of this mower even if it died today. It has outlasted many El Cheapo mowers. It has led a hard life, mowing rental property yards, neighbors' yards in addition to my own yard. Other people's yards are rough on mowers as you aren't familiar with obstacles hidden in high grass & weeds - sticks, rocks, chunks of brick & conc block, pieces of pipe, etc. I have replaced the blade at least 3 times that I can recall. As I don't mulch I choose a hi-lift non-mulching blade for better ejection.

GH did manage to lose the bag one time when I took the mower in for warranty repair. They would not admit that the bag was on the mower when I brought it in, so I had to buy another bag for $50 (now $180.78 frame + $86.99 bag!!), which they said was their cost (they had it in stock and were unlikely to sell it to anyone else - same for the $25 side discharge chute).

The crankshaft has withstood abuse that would have bent lesser mowers' shafts. I have bent blades so badly that I couldn't get them really straight again with bench vise, hand sledge, crescent wrench. The drive bosses on the blade mount plate sheared off, so the blade is strictly friction drive now. Still the c/shaft runs true. A straight blade is true within 1/32" at its tips at any position relative to the drive plate.

Most of the plastic trim crap has fallen off. These bits don't do anything anyway.

When this mower dies I will make sure to hang onto the wheels. They have grease fittings. One had an oversize hub bore that allowed the ball bearing cup to rotate in the hub. I fixed that by removing the wheel, dropping the bearing out and rapping the hub tube with a hammer and punch to make the bearing cup fit snugly.

The tires are still in good shape, not worn much.

I'm replacing the pull cord for the fourth or fifth time. It's not too hard - 4 screws hold the recoil housing to the shroud and one #3 Pozidriv screw holds the recoil sheave assembly into the housing.

It needs a fuel tank top mounting sems screw ($7.55 from LB) again. Despite checking tightness of the screws I've lost the second of these 3/8" head, star drive screws. I had to replace a bushing in one of the fuel tank mounting ears when a screw came loose and the bushing popped out. Fortunately it was a stock bushing from the hardware store for a few cents as LB no longer supplies it. It is necessary as the screw must be tightened against it, not squashing the plastic fuel tank ear.

It managed to eject the upper muffler shield/shroud screw, a $6.37 item from LB.

Recently the blade shot something that knocked the rear access door off and bent it all out of shape. I think it may have come loose and fallen into the blade (?) $29.02 from LB if I can't beat it back into shape well enough to reinstall. Maybe its screw (91c) came loose and dropped it into the blade?

Like any mower, the LB cuts best with a really sharp blade. I sharpen it by draw filing the blade held in a bench vise. I draw file the bottom of the edges flat so the bottom of the edge is horizontal. New blades have a severe rake to the bottom of the edge, which leaves a weak edge that is easily damaged and tends to grab objects like sticks. I do file the top of the edge to the original angle. This method of sharpening has done me well over the last 30+ years of mowing. Blades I have seen that were sharpened by (supposedly) professionals had goofy angles, mounted on the mower upside down, missing blade centering bushing, etc.

I think I'll install a plate on the underside of the deck to reinforce the deck before the left side breaks off. Aluminum alloy if I can find it, otherwise steel. And a liner for the rim of the deck, too, welded to the plate. I hope this will get me many more mowings out of this great mower.

I ran out of LB 2 stroke oil and used Briggs & Stratton 2 stroke oil. It smokes and stinks at 50:1 (original LB spec is 64:1, probably for emissions rating?). My chainsaw and auto repair friend recommended not going with 64:1 if I wanted my engine to live long. I am going to try to get more LB oil. Or if I can't find it, one of the premium synthetics. LB 2 stroke oil is really expensive by internet ordering - the shipping runs the cost way up.