One Day of Preparation Will Produce Days of Productivity
Machine-shed gremlins love to mess with self-propelled sprayers. Experts say a day of preventive maintenance and preparation before heading to the field can thwart gremlin damage and improve sprayer performance.
Self-propelled sprayers, like any machine coming out of storage, benefit from basic mechanical maintenance.
"We sometimes get complaints about machines lacking power when they come out of storage," says Craig Parr, ag service manager at Nebraska Machinery Company, an Ag-Chem dealer in Doniphan, Neb. "New fuel filters are often the cure."
Most modern self-propelled sprayers are hydraulically driven, making hydraulic/hydrostatic maintenance critical. Parr recommends following owner’s manual guidelines that may require annually changing hydraulic filters and final drive hub oil.
"Commercial applicators need to change hydraulic oil and filters annually," he says. "Farmers put fewer hours on a sprayer and may be able to just change the filters. Either way, be sure to use the recommended type of oil in the hydraulic system."
Once the engine and propulsion systems are field-ready, systematically check the spray system.
"The big thing to check, pre-season, is strainers," says Todd Brazelton, aftermarket manager at Barker Implement, a John Deere dealer in Winterset, Iowa. "Sometimes when farmers winterize a sprayer [before storage], they don’t get the spray system completely flushed out. Residue sits in the strainers, cakes up and then restricts flow when put to use the next year."
Residue can also affect flowmeter performance. If sprayers have trouble reaching target rates during pre-season testing, contamination in screens and flowmeters is a prime suspect.
Once screens and flowmeters are guaranteed clean, remove all spray tips, put at least 200 gal. of water in the tank and use the sprayer’s pump to flush the entire system. Open and close valves, jiggle boom hoses, raise and lower booms—anything to jostle loose residue that might have collected in low points in hoses and components.
Once the spray system is flushed, dead-head the spray pump to test its capacity. Turn off all boom sections so the spray pump is working against a "closed" system and push to full engine revolutions per minute.
"Dead-headed spray pumps should generate at least 80 to 100 psi," Brazelton says. "Dead-heading pumps at full pressure is also a good way to identify leaks in boom control valves, flow-meters and elsewhere in the system."
Be sure to check the calibration of wheel or radar speed sensors.
"Speed calibration is one of the most important factors for accurate target rates," Parr says. "Any change in the angle or position of the radar unit can change the [speed calibration] number, which affects the target rate."
Calibrating the spray system each year following guidelines in the owner’s manual is optional but strongly recommended, especially with the price of chemicals today, Parr says.
A final tip for chasing gremlins from sprayers is to do all calibration procedures with a half-load of water, under field conditions. Calibrating an empty sprayer on a gravel driveway can produce skewed calibration values that degrade spraying accuracy when later spraying across fresh-worked soil carrying a full load of chemicals.
- Late Spring 2011