All you ever need to do to find the right parts for your mower or give the right information is to take a picture of the white sticker which is usually underneath or right to the rear of the seat.Sorry if this is way too much, but:
Engine Brand Kohler®
Engine Model 7000 Series
Engine Model Number KT735
Engine Displacement 725cc
Engine Output 24HP
Starter Type Electric
Fuel Tank Capacity 3.0 gal. US (11.36 L)
Cylinders Twin
Engine Start Ignition Key
Engine Oil Capacity 2.0 qt. US (1.89 L)
Lubrication Fully pressurized
Charging System 12 amp regulated
Fuel Gauge No
Governor Mechanical
Choke Separate Choke
Air Filter Dual element
Oil Filter Yes
Fuel Delivery Carburetor
Battery
Battery 210 CCA
Battery Type AGM (Absorbent Glass Mat)
Battery Voltage 12V
Drive System
Transmission Tuff Torq® K46
Forward Speed 5.5 MPH / 8.6 km/h
Reverse Speed 3 MPH / 4.8 km/h
Rear Axle 3/4"
Drive System Hydrostatic
Transmission Control Foot Pedal
Transmission Housing Aluminum
Rear Differential Lock No
Cutting Deck
Deck Cutting Width 50 in
Deck Wash Yes
Deck Material 11-gauge steel
Deck Engagement (PTO) Electric
Deck Construction Fabricated
Blade(s) Three
Deck Lift Manual
Cutting Height Range 1" - 4"
Anti-Scalping Four gauge wheels plus roller
Deck Positions 12
Chassis
Frame Robotically welded
Turning Radius 16"
Bumper No
Rear Tow Hitch Yes
Corrosion Protection Yes
Front Pivot Bar Cast iron
Controls
Cruise Control Yes
Brakes Disc
Comfort
Seat Type 15" high-back
Armrests No
Seat Adjustment Lever
Floor Mats Rubber
Wheels
Bearing Type Poly Bushing
Rear Tires 20"x 8"-8"
Front Tires 15"x 6"-6"
Tire Tread Turf Saver
Specifications
Series XT1® Enduro Series™
Additional Specifications
Hour Meter Available Separately
Mulch Kit Available Separately
Headlight(s) Dual-LED
Cup Holder Yes
Operator Presence System Yes
Model Number 13AQA1TLA10
The two most important things on that are the model number and the serial number.
Now for engine parts you need the sticker on the side of the engine which will have model and serial number and spec.