Model and Serial Numbers

MTD Vertical Engine Model Designators

Starter/Alternators 1=Recoil start2=Electric start (12V)3=E. start/alt. 18W4=E. start/alt. 3A/5A5= AutoChoke/ Recoil6= AutoChoke/Electric Start

1 P 6 1 M U A

P= Vertical (1 cyl.)

Q= Vertical (2 cyl.)

Bore Dia. (mm)

End ProductB 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 TillerL Log splitter W World Tiller

ComplianceU United States (50 State)H EuropeC California0 (Zero) 49 StateG U.S.(49) and EuropeW U.S.(50) and Europe

Major Revision

Change

MTD Horizontal Engine Model Designators

1 6 1 - S H A

Bore Dia. (mm)

Starter/Alternators1=Recoil start2=Electric start3=E. start/alt. 20W/20W4=E. start/alt. 3A DC/5A

End ProductC Chipper/ShredderJ Snow/No tankL Log splitterR Tiller (slow reverse)S SnowT TillerV Verticutter

ComplianceU United States (50 State)H EuropeC California0 (Zero) 49 StateG U.S.(49) and EuropeW U.S.(50) and Europe

Major RevisionChange

MTD Engine Serial Numbers

Model number

1P65FH/0510271A0023

MonthYear

Producing Line# and Shift#:1A=Line 1, 1st Shift1B=Line 1, 2nd Shift2A=Line 2, 1st Shift2B=Line 2, 2nd Shift3A=Line 3, 1st Shift3B=Line 3, 2nd Shift

Date

Engine number

• Three basic series

• Same basic design

• The main difference between engines in the same series is the flywheel and module

Vertical Shaft

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.

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.

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.

Dual Element Air Filter

Foam pre-cleaner, pleated paper filter with debris ejection slots provide superior protection.

RFI/EMI Shielded Plug Boot

Shielded plug boot with the resistor spark plug will dramatically reduce the amount of unwanted electrical noise.

Heavy Duty Crankshaft Ball Bearing

Can withstand higher loads and reduces wear caused by oil contamination or low oil conditions.

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.

Engine Features - Benefits

Horizontal engines

The differences between the snow and tillers engines are:

• Different mufflers

• Different air intake

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• 3-Year Residential / 1-Year Commercial

Warranty

• 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

A review of basic carburetor theory

CarburetorsThrottle body

Ventri

Fuel chamber

(Float bowl)Fuel pick up tube

Carburetors

Throttle plate

Metering jet

Bowl vent

Air bleed

Emulsion tube

Carburetors

Idle circuit

Idle port

Transition ports

Idle air bleed

Fuel and air mix Idle jet

Choke Increased

Vacuum Low pressure

Carburetors

Carburetors

Carburetors

Jets vs. Needle screws

Jet

Needle screw

Why are jets better than needle screws?

What is Vapor lock?

Vapor Lock

Same opening area as the needle screw

VAPOR LOCK

Troubleshooting and Failure Analysis

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.

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.

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.

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.

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.

Troubleshooting the fuel system

• Drain and replace the fuel.• Check the drained fuel for:1. Dirt2. Water3. Is it stale?4. Alcohol• Check fuel tank, lines and vents• Check the carburetor

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.

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.

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.

Troubleshooting an Engine That is Hard to Pull

If the rope pulls out some then stops:

1. Check for hydro-lock.

2. Make sure the blade is not binding.

3. With the plug removed turn the blade, If the blade turns look at the starter.

4. Check for debris trapped in the blade brake.

5. Open the engine.

Troubleshooting an Engine That is Hard to Pull

A jerky starter rope:

1. Check the valve lash!!!2. Check the flywheel for a sheared or

missing key.

3. Check the ACR on the cam.

4. Check the cam timing.