Solo 420 2-Liter One-Hand Pressure Sprayer with Adjustable Telescoping Wand

Q: On top of the unit is a picture of an oil can and the word "OIL"Why does it need oil? What kind of oil and where does it go?

The reference to oil is sort of misleading. The "O" ring in the piston pump needs to be protected from drying out, specially if it is stored and not used. They really should have labeled it Grease because it helps keep the piston plunger O ring soft and supple to make a tight seal in the piston tube. The pump actually pumps air into the container to pressurize the tank containing your selected chemical mixture. Since the "O" ring is not lubricated by any fluid it can dry out and not make a proper seal. If you google "solo handheld sprayer lubrication" there is a link to a PDF from forestry-suppliers on the 400 series sprayers that says "Lubricate O-ring in pressure relief valve with non-water soluble grease on a regular basis. Petroleum Jelly works fine! On the Solousa.com site under support, handheld sprayers, service & repair there is more info on the care and maintenance of these sprayers along with instructions. But they really should have labeled it GREASE and Not OIL!

Q: What is the distance of the stream? How far will the stream shoot?

Adjust the nozzle, 6 to 8 feet.

Q: Would this sprayer work for applying waterproofing/fabric guard on a Sunbrella boat cover? Does it have a good adjustable nozzle?

It depends on how thick/viscous the solution is. I use mine for applying deer-repellent liquid on plants; it is fairly thick and sometimes (maybe once per season) the sprayer pick-up tube has to be unclogged. Yes, Solo nozzles are fairly adjustable.