John Deere’s . Its describes a Briggs & Stratton model 31 single-cylinder engine and a five-speed Dana 4360 gear transaxle. Check the tractor PIN, fitted engine and mower deck before using these figures to order parts. The I9 LA105 row does not give a horsepower rating.
LA105 specifications in Deere’s I9 manual
| Item | Documented information | Check on the tractor |
|---|---|---|
| Manual coverage | LA105, “PIN (300001-)” in Deere’s manual | Read the complete tractor PIN on the left side of the frame. |
| Engine | Briggs & Stratton model 31; single cylinder; 500 cc | Record the installed engine model and serial number. |
| Transmission | Dana 4360 gear transaxle; five forward speeds | Confirm the controls and fitted transaxle, especially if a sale listing says “hydrostatic.” |
| Fifth forward gear | 8.0 km/h (5.0 mph) listed travel speed | Treat this as a manual specification, not a measured speed for a used tractor. |
| Oil filter | “Yes” in the I9 LA105 engine row | Identify the installed engine before buying a filter. |
| Horsepower | No figure in the I9 LA105 specification row | Check an engine label or documentation for a particular machine instead of inferring power from its model badge. |
A listing headed “19 HP” or “19.5 HP” does not establish a rating for every LA105. The cited I9 row supplies no horsepower number, and an older tractor may have a replacement engine. The same manual lists the adjacent LA115 as an automatic model; do not transfer that transmission specification to an LA105.
Match the deck before buying belts or blades
Deere published both an and a for an LA105 with a 42-inch deck. Both list mower belt GX20072. Their blade entries differ: the maintenance sheet lists GY20850 as a packaged two-blade kit, while the 2023 guide lists UC21583 as a 7-lobe mower blade. The lists differ. Neither tells you what is mounted on a particular used deck, or whether the blades interchange.
- Record the full tractor PIN, installed engine model and deck serial number. Deere’s I9 manual places the tractor PIN on the left side of the frame; the maintenance sheet leaves separate spaces for tractor and deck serial numbers.
- Read the identification on the deck itself and compare its blade mounting and part listing with Deere’s current parts catalog for that tractor and deck.
- If the deck tag is missing or the guides disagree with the installed parts, give a Deere parts counter the tractor PIN, deck details and clear photographs before placing an order.
Checks when considering a used LA105
Ask the owner to show the tractor PIN and engine marking, then compare them with the applicable manual and service records. For an I9-covered machine, ask for a demonstration of gear selection, reverse and braking on clear, level ground. If its controls are described as pedal-controlled hydrostatic drive, resolve that mismatch before treating the listing as an I9 gear-model LA105.
With the engine stopped and key removed, visually inspect the fitted deck, belt, guards and blade mounting for damage or missing hardware. Use the operator manual that matches the PIN for brake and safety-system checks. A failed brake or safety interlock needs correction before operation. Service records and a model decal cannot substitute for identifying the fitted engine and deck when choosing filters, belts or blades.