Used Sprayer Inspection Checklist: What to Check Before You Buy a Self-Propelled Sprayer

Buying used · 7 min read

← Back to blog

A used self-propelled sprayer can cover a lot of acres for a fraction of new iron, but it's one of the most complex machines you'll ever buy secondhand: a chemical system, a hydraulic system, a boom the width of a football field, and a cab full of electronics all riding on the same chassis. Problems hide in the plumbing and the wiring. Here's a field-by-field checklist to work through before money changes hands.

Start with the boom: folds, breaks, and level

The boom is where wear lives. Walk the full length of it, both sides, and look at every weld on the boom sections — cracks start at welds and stress points, especially near the hinge points and breakaway joints. Check the quality of any previous weld repair: a clean, continuous bead is fine; globs of weld over cracked tubing with visible rust is a boom that will fail again.

Work the boom through its full fold and unfold cycle. It should move smoothly with no binding. Check that each section locks in the spray position with no sag. While it's unfolded, sight down the boom from one end — a boom that waves or sags in the middle will never spray evenly.

Exercise the breakaway hinges. Every breakaway should swing freely and snap back to center. Seized breakaways mean the next fence post bends tubing instead of folding a section. Check the cables or linkages that keep the boom level, and the height control system. If it has automatic boom height, watch the sensors respond as the boom moves.

The boom plumbing: hoses, fittings, and nozzle bodies

This is the part sellers rarely clean, which works in your favor. Look at every hose on the boom for chafing, cracking, and soft spots, especially where hoses rub against boom tubing. Check each fitting for white crust or staining — dried chemical residue at a fitting is a weep, and weeps on a sprayer mean uneven rate.

Pull a few nozzle bodies apart. Look for corroded check valves, cracked screens, and missing strainers. A machine with clean screens and intact check valves was maintained; one with dry, cracked, and missing screens tells you the whole plumbing system got the same attention. Check that nozzle spacing is consistent tip to tip.

Rate controller and electronics: the expensive bits

Power up the display and work through every menu slowly. You want to see: GPS signal acquisition, section control responding, boom height reading (if equipped), and the flow meter showing a reading when the pump runs. Toggle each boom section on and off from the cab and confirm the indicator on the display matches. A section that shows "on" but doesn't spray, or sprays when shown "off," is a wiring or solenoid problem you'll inherit.

Check the harness along the boom. Wiggle connectors and watch the display for dropouts. The boom harness takes constant flexing every fold cycle, and chafed wires inside the loom are the classic intermittent failure — fine in the yard, dead in the field.

Verify the display's software versions, and ask whether the receiver unlocks transfer with the machine. Section control, auto-steer, and boom height each commonly need paid unlocks tied to the display or the receiver — if one you need was tied to the seller's account and doesn't transfer, know that before you negotiate.

Tanks, chemical induction, and cleanout

Inspect the main product tank inside and out. Look for stress cracks around the mounting points, the fill opening, and the sump. Check the sight gauge or level sensor against a known quantity; a level sensor that's been wrong for years means every load ticket the seller kept was approximate.

Work the chemical induction system: the inductor hopper, its rinse nozzle, and every product valve. Valves that are seized open or closed suggest a machine that wasn't flushed properly. Look for clean plumbing and no crusted residue in the inductor — that's evidence of a real cleanout routine. Check the rinse system; a working fresh-water rinse tank with a working pump is what lets you switch chemistries safely and keeps valves and screens alive.

Engine, cooling, and the drive train

Check it like any diesel: cold start it if you can. Hard starting, excessive smoke that doesn't clear, or a starter that labors all point at engine or battery issues worth investigating. Let it idle and walk around — listen for knocks, watch the exhaust color, and check every fluid for the right level and condition. Milky oil or coolant that smells like exhaust are stop-the-deal findings.

Look at the cooling package. Sprayers run in dusty conditions and the radiators and oil coolers cake up. Check between the cores for packed debris. Overheating in the field traces back to a dirty cooling package more often than to anything mechanical.

Inspect the drive: check for leaks at the wheel motors and drive lines, and look at the condition of the hydraulic fluid — dark and burnt-smelling fluid is a system that's been neglected. Cycle the steering lock to lock and feel for roughness or dead spots.

Suspension, frame, and the underside

Self-propelled sprayers ride on suspension systems — coil, air, or hydro-pneumatic — and those systems take a beating. Bounce each corner and watch the rebound. Air systems should hold pressure; if the compressor cycles constantly or the machine sits low on one corner, there's a leak or a bad strut. Check every suspension bushing and pivot for play.

Get under the machine and inspect the frame and chassis. Look for cracks at suspension mounting points and at the tank cradle. Check the clearance system — cycle it fully if it's adjustable. Anything that binds or won't reach full travel is a problem when you need clearance in tall crops.

Tires and wheels

Sprayer tires are tall, narrow, and not cheap. Check all four (plus any duals or floaters) for sidewall cracking, stubble damage, and uneven wear that points at alignment or suspension problems. Look at the rims for cracks around the lug holes and check that every lug is present and tight. Note the tire size and row spacing compatibility — if you're on 30-inch rows, make sure the track setup actually fits your rows.

The cab: controls, visibility, and air

Sit in the seat and touch every control. The joystick or drive lever should move smoothly through its range with no dead spots. Test the lights, wipers, washer, mirrors, and the camera system if it has one — night spraying and end-of-row turns depend on them.

Check the cab air filtration. A working charcoal filter and sealed cab matter for operator safety with chemicals, and a cab that's been dusty for years will show it in the HVAC vents and behind the seat. Run the air conditioning hard — it needs to keep up on a hot afternoon. Look at the door seals; doors that won't seal let dust and drift into the cab.

Records to ask for

Ask for the same records you'd want on any machine: service history and any major repairs. Specifically for a sprayer, ask: when was the flow meter last calibrated, when were the nozzle bodies and screens last serviced, and what's been replaced in the electronics. Ask how the machine was stored and how it was winterized — sprayers that sat with water in the plumbing freeze-crack pumps and valves. Ask what acres it covered per year — a machine that ran 15,000 acres a year of custom work is a very different machine than one that ran 3,000 on the home farm.

The live test run

Don't buy a sprayer you haven't seen spray. Have the seller fill the tank with water and run a full cycle: pump up, unfold the boom, and spray at operating pressure while you walk the boom. Watch for weeps at fittings, listen for pump cavitation, and confirm every section toggles on and off from the cab. Watch the rate controller hold rate while the speed changes — that's the whole job of the system, and it should be rock steady.

If you can, do a nozzle uniformity check: run water for a set time into a row of catch containers, one per nozzle, and compare volumes. You're not looking for laboratory precision — you're looking for the nozzle that's dribbling at half rate or the one stuck wide open.

Bring a second set of eyes

A self-propelled sprayer is too complex and too expensive to evaluate alone on enthusiasm. If you can, bring your mechanic or a tech from your dealer to the inspection — they've seen the failure patterns on the exact model you're looking at. And if the seller won't let you fold the boom, run the pump, or power up the display, that's the answer: walk away.

The Used Equipment Analyzer can help before you even drive out — upload the listing photos and get an AI inspection report flagging visible wear, damage, and red flags on the machine you're considering. It's one more filter before you spend a day on the road.