Model and Serial Numbers

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Model and Serial Numbers
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MTD Vertical Engine Model Designators
1 P 6 1 M U A

• Starter/Alternators 1Recoil start
• 2Electric start (12V)
• 3E. start/alt. 18W
• 4E. start/alt. 3A/5A
• 5 AutoChoke/ Recoil
• 6 AutoChoke/Electric Start

Major Revision Change
Compliance U United States (50 State) H Europe C C
alifornia 0 (Zero) 49 State G U.S.(49) and
Europe W U.S.(50) and Europe
P Vertical (1 cyl.) Q Vertical (2 cyl.)
Bore Dia. (mm)
End Product B Mower (long shaft
M0) C Chipper/Shredder M Mower (long shaft/no
shroud) D Mower (long shaft M1) N Mower (short
shaft M0) E Mower (short shaft M1) P Mower
(long shaft M0) F Mower (short shaft/no shroud)
Q Mower (short shaft M0) I Mower (long shaft/M0)
T Tiller L Log splitter W World Tiller
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MTD Horizontal Engine Model Designators
1 6 1 - S H A
Starter/Alternators 1Recoil start 2Electric
start 3E. start/alt. 20W/20W 4E. start/alt. 3A
DC/5A
Major Revision Change
Compliance U United States (50 State) H Europe C C
alifornia 0 (Zero) 49 State G U.S.(49) and
Europe W U.S.(50) and Europe
Bore Dia. (mm)
End Product C Chipper/Shredder J Snow/No
tank L Log splitter R Tiller (slow
reverse) S Snow T Tiller V Verticutter
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MTD Engine Serial Numbers
1P65FH/0510271A0023

• Model number

Month
Year
Date
Producing Line and Shift 1ALine 1, 1st
Shift 1BLine 1, 2nd Shift 2ALine 2, 1st
Shift 2BLine 2, 2nd Shift 3ALine 3, 1st
Shift 3BLine 3, 2nd Shift
Engine number
5
Vertical Shaft

• Three basic series
• Same basic design
• The main difference between engines in the same
  series is the flywheel and module

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Engine Features - Benefits
Electronic Ignition Capacitor Discharge Ignition
provides higher ignition voltage required for
easy, dependable starting with no maintenance.
Forged Steel Crankshaft Better strength/weight
ratio than cast iron which means stronger and
more durable.
Heavy Duty Crankshaft Ball Bearing Can withstand
higher loads and reduces wear caused by oil
contamination or low oil conditions.
RFI/EMI Shielded Plug Boot Shielded plug boot
with the resistor spark plug will dramatically
reduce the amount of unwanted electrical noise.
Mechanical Governor Provides precise control of
engine speed and responds 30 faster to sudden
load increases than traditional air vane designs.
Results in smoother, consistent, and trouble-free
cutting power.
Overhead Valve Design with Cross-flow Cylinder
Head More efficient, cleaner burning engine.
Results in more power and reduces fuel
consumption when compared to conventional
side-valve engines.
Dual Element Air Filter Foam pre-cleaner, pleated
paper filter with debris ejection slots provide
superior protection.
Cast Iron Cylinder Sleeve Automotive style piston
and rings riding in a cast iron sleeve cylinder
provides longer life while reducing bore wear and
oil consumption.
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Horizontal engines

• The differences between the snow and tillers
  engines are
• Different mufflers
• Different air intake

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MTD Snow Engine

• OHV with Cross-Flow Cylinder Head Design
• 208cc Engine Displacement
• Cast Iron Cylinder Sleeve
• Forged Steel Crankshaft
• Cast Iron Camshaft
• Heavy Duty Crankshaft Ball Bearings
• Mechanical Governor
• Mechanical Compression Release
• Extended Oil Fill Dipstick
• Extended Oil Drain
• 2 Quart Industrial Steel Fuel Tank
• Large Automotive Style Ratcheting Fuel Cap
• Ergonomic Oversize Mitten Grip Handle
• Push/Pull Safety Key Switch
• Low Tone Muffler with Heat Shield
• Push Button 110V Electric Starter UL/CSA Approved
  
• Alternator for Lights Optional Heated Hand
  Grips
• IDI Ignition
• Resistor Spark Plug with RFI/EMI Shielded Boot

9

• OHV with Cross-Flow Cylinder Head Design
• 208 cc Engine Displacement
• Cast Iron Cylinder Sleeve
• Forged Steel Crankshaft
• Cast Iron Camshaft
• Heavy Duty Crankshaft Ball Bearings
• Mechanical Governor
• Mechanical Compression Release
• Extended Oil Fill Dipstick
• 2 Quart Industrial Steel Fuel Tank
• Large Automotive Style Ratcheting Fuel Cap
• Variable Speed Control
• Low Tone Muffler with Heat Shield
• Induction Discharge Ignition
• Resistor Spark Plug with RFI/EMI Shielded Boot
• 2-Year Residential / 1-Year Commercial Warranty

New Tiller Engine for 08
Featured on Troy-Bilt Bronco Super Bronco Models
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A review of basic carburetor theory
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Carburetors
AIR
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Carburetors

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Carburetors
Fuel and air mix
Increased Vacuum

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Carburetors

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Carburetors

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Carburetors

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Jets vs. Needle screws
Why are jets better than needle screws?
Needle screw
VAPOR LOCK
Jet
Vapor Lock
What is Vapor lock?
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Troubleshooting and Failure Analysis
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When troubleshooting an engine, Diagnose with
Eyes Open!

• First, check the oil
• What does this tell you?
• Take a look at the air filter
• What condition is it in?
• Fuel
• A big problem area.

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• Cleanliness
• Good indicator of the level of care and type of
  use.
• Signs of mouse nest?
• Mud-packed / covered with wet grass?
• Safety
• Guards in place? Safety bail disabled?
• Pull the rope
• Pull too easily?Got compression?
• Pull too hard?Crankshaft straight?Hydro-lock?
• Jerks back?Flywheel key?Blade on tight?
• Starter rope broken?Probably a reason.

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Troubleshooting

• Periodic maintenance will solve a lot of
  performance issues.
• Check valve lash, oil, fuel, and all filters
  before troubleshooting.
• NOTE Most jerky starts on the MTD engine are
  due to loose valve lash.
• Inspect/replace the spark plug.

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Troubleshooting

• Ignition- sufficient spark to start combustion in
  the cylinder, occurring at the right time.
• Compression- enough pressure in the cylinder to
  convert combustion into kinetic motion. It also
  needs sufficient sealing to generate the vacuum
  needed to draw in and atomize the next intake
  charge.
• Fuel- correct type and grade of fresh gasoline
  in sufficient quantity, atomized (tiny droplets)
  and in correct fuel/air proportions.
• Flow- if all of the above conditions are met, but
  the flow of air is constricted on the inlet or
  exhaust side it will cause the engine to run
  poorly or not at all. This also includes the
  ensuring the valves are timed to open at the
  proper time.

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Troubleshooting

• Isolate the fuel system first by performing a
  prime test.
• Squirt clean, fresh fuel into the throat of the
  carburetor.
• If the engine starts and burns the prime, the
  problem is in the fuel system.

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Troubleshooting the fuel system

• Drain and replace the fuel.
• Check the drained fuel for
• Dirt
• Water
• Is it stale?
• Alcohol
• Check fuel tank, lines and vents
• Check the carburetor

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Troubleshooting the Ignition System

• Check for spark using a spark tester.
• Never ground a sparkplug against the head! The
  fuel/air mix coming out of the spark plug hole
  can ignite.

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• If there is no spark
• Check the blade brake switch.
• Check the air gap of the module.
• Check the ground on the module.
• Check the flywheel key.
• If every thing checks out OK, replace the module.

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Troubleshooting Compression

• If there is spark, check the spark plug again. If
  it is wet, the plug is bad. If it is dry, do a
  compression test.
• Near zero compression is most likely a stuck
  valve or valve lash is to tight.
• Low compression, look at the valve seats and
  piston rings.
• High compression is most likely excessive valve
  lash, a block muffler or a partial hydro-lock.

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Troubleshooting an Engine That is Hard to Pull

• If the rope pulls out some then stops
• Check for hydro-lock.
• Make sure the blade is not binding.
• With the plug removed turn the blade, If the
  blade turns look at the starter.
• Check for debris trapped in the blade brake.
• Open the engine.

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Troubleshooting an Engine That is Hard to Pull

• A jerky starter rope
• Check the valve lash!!!
• Check the flywheel for a sheared or missing key.
• Check the ACR on the cam.
• Check the cam timing.