John Deere Z445 sits in most Midwestern garages because it mows fast, rides like a go-kart, and still fits through a suburban gate. If you own a Z445 mower or are planning to buy one used, this quick read collects the key specifications, problems that will happen, and must-have parts so both first-time owners and seasoned techs can keep the machine cutting clean.
John Deere Z445 Spec
Engine
| Engine Info | Kawasaki FH721 gasoline 2-cylinder air-cooled vertical-shaft V-Twin |
|---|---|
| Displacement | 675 cc 41.2 ci |
| Bore/Stroke | 2.96×2.99 inches 75 x 76 mm |
| Power (gross) | 25 hp 18.6 kW |
| Starter | electric |
| Starter volts | 12 |
| Oil capacity | 1.6 qts 1.5 L |
Transmission
| Transmission | Kanzaki DUP-10 |
|---|---|
| Type | hydrostatic |
| Gears | infinite forward and reverse |
Dimensions
| Tires | Lawn/turf front: 13×5.0-6
Lawn/turf rear: 22×9.50-10 |
|---|---|
| Wheelbase | 48 inches 121 cm |
| Length | 74.7 inches 189 cm |
| Height | 42.5 inches 107 cm |
| Weight | 680 lbs (54 deck) 308 kg |
Attachments
| Feature | 48″ Mower deck | 54″ Mower deck |
|---|---|---|
| Brand | John Deere | John Deere |
| Cutting Width | 48 inches 121 cm |
54 inches 137 cm |
| Total width | 62.7 inches 159 cm |
68.9 inches 175 cm |
| Number of Blades | 3-blade | Not specified |
| Lift Type | manual lift | manual lift |
| Discharge Type | right-discharge | right-discharge |
| Cut Height Range | 1 to 4 inch 2 to 10 cm |
1 to 4 inch 2 to 10 cm |
Source: https://www.tractordata.com/lawn-tractors/004/1/2/4129-john-deere-z445-attachments.html
Compared to the Z425, the Z445 mower with a 25 HP block, giving a blade-tip speed that steps up a notch, letting you knock down spring fescue without bogging. Meanwhile, an 8 mph top end means you can cover 2 acres in under an hour if the terrain is flat and open—handy when rain clouds start stacking over the cornfield.
Common JD Z445 Problems
Weak or Failing Fuel Pump
If your Z445 sputters under load or struggles to restart when hot, the vacuum-operated fuel pump may be losing efficiency. This is especially common around the 250-hour mark. Replacing it with a high-flow, OEM-style unit restores steady fuel delivery. It’s a 15-minute job with basic tools.
Hard Start & Surging
Owners report the engine running fine for 10 minutes and then quitting cold. A blocked fuel-cap vent starves the carb; swapping the $12 vented cap restores flow in five minutes.
Hydro Weak on One Side
If the mower lists like a bass boat, chances are the Kanzaki DUP-10 pump has scored brass plates or debris from a cracked wheel-motor shaft. Rebuilt kits exist, but most shops simply bolt in a new AM136028 pump to save labor.
Dirty or Clogged Air Filter
Cutting dry grass in dusty fields chokes the air filter fast. Restricted airflow causes rich running, black smoke, and sluggish throttle response. Hold the old filter up to the sun. If light barely gets through, it’s time for a new one. Foam pre-filters help extend service intervals.
Intermittent Shut-Off on Slopes
The seat-safety switch loosens over time, cutting spark when the operator leans uphill. A dab of dielectric grease plus reseating the connector usually cures the phantom stall.
Failing Ignition Switch
Random no-starts or needing to jiggle the key are classic signs. Internal contacts wear out or corrode—especially after wet winters or pressure-washing the dash. A drop-in switch with matching keys takes 5 minutes to swap. Keep a spare in your toolbox if your unit’s over 5 years old.
If you plan to upgrade or replace, the following reference table can be your consideration.
Bonus Tip: Keep Mice Out
Rodents love building nests behind the engine shroud. They chew wires and block cooling airflow. Pull the cover every spring and check for signs. A $3 peppermint oil pouch often keeps them out.
Related John Deere Z445 Parts
To know more, please view the complete John Deere Z445 parts catalog.
Practical Tips for Mower Owners
Deck Choice & Property Size
A 54 in deck saves one pass on every 5,000 ft² strip but adds 15 lb up high—noticeable on side-slopes above 10°. A 48-inch deck paired with turf tires keeps the center of gravity lower and protects tree roots.
Fuel Strategy
The small 3.5 gal tank encourages running E10 from the corner station. Adding a $4 ounce of marine-grade stabilizer every fill halves reports of varnished carbs and sticky needles in spring start-ups.
First Oil Change Matters
One gallon of 20W-50 and a $40 filter every 100 hours beats a $900 motor swap. Break-in metal fines peak by 50 hours, so don’t skip that first change even if the fluid still looks amber.
Conclusion
Knowing the exact spec sheet about John Deere Z445, watching for tell-tale hiccups, and stocking mission-critical parts keeps downtime to a beer break instead of a lost weekend. Ready to use OEM-grade parts with a one-year warranty, 90-day returns, fast shipping, and affordable prices? Check the John Deere parts catalog and get your mower back to full throttle today.
