Part of the John Deere Repair Manuals.
This is the factory technical manual John Deere dealers used to service the LA100 series: LA105, LA115, LA125, LA135, LA145, LA155, LA165 and LA175 lawn tractors built from 2005 to 2010. It covers both the single-cylinder gas engines and the V-twins, with engine identification, tests and adjustments, repair specs and torque specifications. You also get electrical troubleshooting for starting problems, fuel shutoff solenoid and battery testing, plus power train coverage of the T40 and K46 hydrostatic transaxles, steering, brakes and deck attachments. The specifications section lists metric and inch fastener torque charts, gasoline requirements, oil viscosity and grease grades. If your tractor cranks but will not fire, or drives weak up a hill, the answers are in here.
What's Inside This John Deere LA105–LA175 Manual
| System | Pages | Key Topics |
|---|---|---|
| Safety | 4-8 | Safety Symbols and Signal Words, Battery Safety, Fire Prevention, Protective Clothing, Chemical Handling |
| Specifications and Information | 9-15 | Metric Fastener Torque Values, Inch Fastener Torque Values, Gasoline Requirements, Engine Oil Viscosity, Alternative Lubricants |
| Engine - Gas | 16-84 | Engine Identification, General Specifications, Tests and Adjustments, Repair Specifications, Torque Specifications |
| Engine - V-Twin | 85-157 | Engine Identification, General Specifications |
| Electrical | 158-249 | Starting Problems, Fuel Shutoff Solenoid Test, Battery Testing |
| Power Train | 250-321 | Transaxle Serial Number, Hydrostatic Transmission Oil |
| Steering | 322-337 | General Maintenance |
| Brakes | 338-353 | Parking Safely |
| Attachments | 354-393 | General Safety |
| Miscellaneous | 394-402 | Manual Description, Tools and Materials, Hood Removal and Installation |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Unleaded gasoline | ||
| Gasoline octane rating (anti-knock index) | 87 or higher | p. 12 |
| Gasoline ethyl or grain alcohol blend limit | 10% by volume | p. 12 |
| Gasoline methyl tertiary butyl ether (MTBE) blend limit | 15% by volume | p. 12 |
| 4-Cycle Gasoline Engine Oil | ||
| Engine oil API service classification | SG or higher | p. 13 |
| Break-In Engine Oil | ||
| Break-in engine oil API service classification | SE or higher | p. 13 |
| Break-in period | 5 hours (maximum) | p. 13 |
| General all-purpose grease | ||
| Grease NLGI grade | No.2 | p. 14 |
| All Models | ||
| Grease effective temperature range | -29 to 135 degrees C (John Deere greases) / -20 to 275 degrees F (John Deere greases) | p. 14 |
| Transmission model | T40 (Transmissions) / K46 (Transmissions) | p. 15 |
| Transmission optional fill oil | J20C Hygard Hydraulic oil (T40 or K46 transmissions) / 5W-50 Synthetic Engine Oil (T40 or K46 transmissions) | p. 15 |
| Spark Plug Gap | 0.76 mm (0.030 in.) | p. 17 |
| Spark Plug Torque | 20 N•m (180 lb-in.) | p. 17 |
| Valve Clearance - Intake | 0.08 - 0.13 mm (0.003 - 0.005 in.) | p. 17 |
| Valve Clearance - Exhaust | 0.13 - 0.18 mm (0.005 - 0.007 in.) | p. 17 |
| Magneto Air Gap | 0.25 - 0.35 mm (0.010 - 0.014 in.) | p. 17 |
| Crankcase Oil Capacity | 1.4 L (1.5 qt) | p. 16 |
| Fast Idle Speed | 3350 ± 100 rpm | p. 17 |
| Machines | ||
| Transmission type | Hydrostatic | p. 14 |
| T40 and K46 transmissions | ||
| Transmission factory fill oil | 10W30 engine oil | p. 15 |
John Deere LA105–LA175 Common Problems This Manual Covers
Hard starting, surging or no-start after storage
Work through the Engine - Gas Tests and Adjustments procedures: check fuel delivery, clean or rebuild the carburetor, replace the fuel filter and spark plug, then verify carburetor settings against the Repair Specifications rather than guessing by ear.
Manual Section: Engine - Gas: Tests and Adjustments p. 23Cranks fine but never fires, or dies when you release the brake
Follow the Electrical section's starting problems diagnosis. It includes the fuel shutoff solenoid test and battery testing, which lets you separate a dead solenoid or weak battery from a failed seat or brake safety switch in a few minutes.
Manual Section: Electrical: Starting Problems / Fuel Shutoff Solenoid Test p. 199Engine overheats or loses power partway through mowing
Pull the shrouds and clean the cooling fins first, then check oil level and grade against the Engine Oil Viscosity chart. The engine General Specifications and Tests and Adjustments sections cover verifying governor and mixture so a lean-running carb does not cook the engine.
Manual Section: Engine - Gas: General Specifications / Tests and Adjustments p. 30Tractor moves weakly or will not pull a grade
Identify your transaxle first using the serial number location in the Power Train section, then confirm the hydrostatic oil is correct: 10W30 factory fill, or J20C Hy-Gard or 5W-50 synthetic as approved alternatives, before condemning the T40 or K46 unit.
Manual Section: Power Train: Transaxle Serial Number / Hydrostatic Transmission Oil p. 250Frequently Asked Questions
My LA115 cranks but will not start, or starts and dies. Where do I begin?
Start with fuel and safety switches before you throw parts at it. On these carbureted tractors the usual suspects are stale gas, a plugged fuel filter, a gummed carburetor or a fouled spark plug, but a failed seat or brake safety switch will also kill spark. The Electrical section walks through starting problems step by step, including the fuel shutoff solenoid test, so you can prove which circuit is dead instead of guessing. p. 22
The oil level on my dipstick is rising and the oil smells like gasoline. Is that serious?
Stop running it. Gas-diluted oil will wipe the bearings, and on these carbureted engines the usual path is fuel weeping past the carburetor inlet needle into the crankcase. The manual does not walk that symptom as a fault tree, but it gives you what the repair needs: full carburetor teardown with float, inlet needle and hinge pin service, and the oil to refill with (SG or higher API, viscosity picked off the temperature chart). Replace the needle and seat, then change the oil before you run it again. p. 41
What oil goes in the K46 or T40 hydrostatic transmission?
Factory fill is plain 10W30 engine oil. The manual also lists J20C Hy-Gard hydraulic oil and 5W-50 synthetic engine oil as approved options. The Power Train section shows where to find the transaxle serial number so you know whether you have the T40 or K46 before you order parts or service it. p. 15
Does the manual give torque specs for blade bolts, spindles and general fasteners?
Yes. There are full metric and inch fastener torque charts in the Specifications and Information section, and the engine chapters carry their own repair and torque specifications for head bolts, flywheel and similar fasteners. I will not quote numbers here because they vary by fastener grade and size - use the charts. p. 355
What gas should I run, and can I use ethanol blends?
Use 87 octane or higher. The manual allows up to 10 percent ethanol by volume or up to 15 percent MTBE. Higher ethanol blends are the fastest way to a varnished carburetor on a machine that sits over winter, which is why fuel-system parts top the replacement list on these tractors. p. 12
