So my Son's 88.5 Samurai (burns?) more oil than any car I've ever owned. 5 quarts in 300miles.
 The compression tested at 110, 110, 110, 90. The number 4 cylinder came up 10 psi to 100psi with a teaspoon of oil added. Truck has 120,000mi on a 1.3L. The spark plugs look OK they are a little white from running lean but they sure aren't oil fouled. No oil in the coolant. Top speed 60mph. Gutless engine but not dangerous. Lift kit + 30 inch tires.
 The truck was a gift from my father-in-law and it had been sitting in a garage for 15 years. A number of the seals leak but nothing that would dump this much oil. No real blue smoke to speak of. some oil smell but not so much that it couldn't be off of the hot engine. As best I can tell the oil warning light doesn't ever come on!!! Exhaust pipe has dry black soot on it.
 He turned 16 last week on the 6th and is planning some weekend wheeling and driving around town. I don't have a plan! oil is cheap, I have told him to check it with every fill-up keep it topped up, and have fun.
 If you have better advice feel free to make suggestions. Remember this is a kid with no job, no girlfriend, no money and a "D" in biology so keep it cheap. I ran junkyard engines in straight motor honey when i was a kid.

Engine is shot. That com presion is way low. Before I rebuilt my tinny, I used a quart every 300=400 miles. Now I just change it and don't have to add any. You'll probably see some smoke if you look while com presion braking going down a hill or on cold morning starts

Old Suzuki's like to mark their territory, drive it and park in over a clean
piece of cardboard or an oil drip pan, and see how many spots you have.

There are a few places that these engines will leak from and given the age
of the Trucklet, I think if you change those seals it will be much better.

First of all, get a new valve cover gasket, and check all of the valves for
the right lash, this is the #1 reason these engines burn valves and get
thrown out, and the second seal that will leak is the O-ring at the back
of the head that seals the distributor housing, and in this case is most
likely your problem, the oil runs down the back and onto the trans and
to the ground, you will not really know it because it is not hitting much
hot exhaust it just runs all over. This is the housing not the o-ring on the
distributor base


Wild

Sounds a lot like the 1.3 in my Swift (same engine, different vehicle) - plugs were never oil fouled, no leaks to speak of, no smoke to speak of, the oil just "disappeared" - the compression is low - it sounds like it's tired, and needs a rebuild.  As you already know, they run surprisingly well given the low compression, but will also run soooo much better if rebuilt.

By the way - were those compression numbers hot or cold - and did you have the throttle blocked wide open?

If biology is the only "D", let him get a job and start saving the pennies - and when he has enough - the two of you tackle it together, it's not a difficult engine to rebuild and will make a nice "father & son" project - you can get the parts you need from Low Range Off Road,

Yaa, my bad on the compression test engine was cold and carb was in typical condition. Maybe add 10-20PSI?

Still low. That and the fact that they go up if you squirt some oil in= bad rings at best. Mine had oval shaped cylinders which is common on a worn 1.3.