Small Engine
Reassembly
Briggs & Stratton OHV
A Visual Guide
Objectives:
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Reassemble an engine following concise steps
and detailed notes taken by the student.
Utilize proper tool techniques.
Reinforce lecture-based theoretical discussions.
Utilize and reference engine standards with
appropriate engine manuals.
Procedure Notes:
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Follow the reassembly steps precisely.
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Be sure to reference notes and sketches you
created during engine disassembly.
Your engine may not be exactly like the engine in
this presentation. Even if your Briggs & Stratton
OHV engine is not exactly like the model used in
this presentation, many of the procedures will be
the same.
Use reassembly grease on all
internal parts and follow all
specifications!
Pre-Assembly Cleaning
Clean all internal parts in the parts cleaning cabinets. Remove
excess solvent with compressed air. Eye protection and chemical
resistant gloves are required.
Step 1: Install the Crankshaft
Pre-operation grease
Reminder: Tapered end to the front of the engine.
Step 2: Reassemble the Piston Rings
and Connecting Rod
Reminder: The rings must be replaced correctly. Review your
sketch of connecting rod and piston ring orientation.
Step 2: Reassemble the Piston Rings
and Connecting Rod
Connecting rod & piston orientation. Arrow
on piston and MAG abbreviation to the
magneto side of the engine.
wrist pin clips
Step 3: Install the Piston and
Connecting Rod in the Cylinder
Reminder: Clean and coat cylinder wall with lubricant. Use
piston ring compressor. Install in the correct orientation.
Step 3: Install the Piston and
Connecting Rod in the Cylinder
Use your thumbs or the
handle of a mallet to gently
insert the piston assembly.
Rotate the crankshaft to prevent
it from striking the connecting
rod during reassembly.
Step 4: Replace Connecting Rod Cap
Short screw and oil splash
away from cylinder
Arrow toward cylinder
Reminder: Lubricate interior of rod cap and connecting rod. Replace cap and rod in the
correct direction. Replace oil splash and rod cap lock. Torque screws properly.
Step 5: Replace Tappets
Note: Lubricate each tappet
Step 6: Replace Cam Gear
Reminder: Make sure journal is secure. Line up timing marks.
Lubricate all bearing surfaces.
Step 7: Install Crankcase Cover
Reminder: Use correct gasket. Tighten bolts in correct sequence by skipping
across the cover. Replace oil seal if needed. Adjust end play if needed.
Step 8: Install Flywheel
Install flywheel
and key.
Install Starter
Cup and Nut
Torque flywheel nut
using a strap wrench
and ft.lb. torque
wrench.
Installing Cylinder
Head & Adjusting
Overhead Valves
Return to your measurement sheets
in Chapter 9 to record your
measurements.
Step 9: Insert Valves Into Head
Insert valves from the bottom of
the head, while using your
thumbs to lock the valve retainer.
Exhaust valve
guide rises
Oil seal on
intake valve
Step 10: Install the Cylinder Head
Reminder: Install head gasket first. Torque head bolts in a crisscross
pattern.
Step 11: Install Pushrods & Valve
Wear Plates
Valve
Wear Plates
Pushrod
Step 12: Align Rocker Arms with Push
Rods & Valve Wear Plates
Reminder: Use the rocker arm as a fulcrum to slightly compress each
valve spring in order to slide its opposite end on top of the push rod.
Step 13: Prepare the Cylinder for
Valve Adjustment
Reminder: Rotate piston to TDC compression. Use a screwdriver in the
sparkplug opening as a guide or align the PTO keyway to the cylinder. Now
rotate the flywheel clockwise until the magnet points straight up. This
disengages the compression release on the camshaft.
Step 14: Check Valve Clearance
Reminder: According to specification, insert a flat feeler gauge
between the rocker arm and valve wear plate. Make
adjustments if out of gap tolerance.
Step 15: Adjusting Valve Clearance
1. Insert feeler gauge
2. Loosen locking screw, while
holding adjustment nut.
3. Adjust clearance with the
adjustment nut.
4. Hold adjustment nut and
lock rocker arm.
Step 16: Replace Valve Cover
Note: Don’t forget gasket. Short bolt to the top.
Step 17: Install
Armature
Note: Thread kill wire through port in block.
Bolt armature to block. Adjust armature air
gap with shim or business card.
Step 18: Insert Heat Shield
Note: One screw only
Step 19: Replace Linkage Plate
Governor
Arm
Insert Kill
Wire
Carburetor
Linkage
4 Bolts
Reminder: Refer to your drawings to ensure all linkage is correctly assembled.
Step 20: Replace Carburetor
1.
2.
Attach spring &
linkage to
carburetor
Insert both
gaskets & spacer.
Step 21: Reset Governor (IMPORTANT)
Set throttle to full
Confirm that throttle
butterfly is open completely
Reminder: Ensure that all linkage travels freely.
Step 21: Reset Governor (IMPORTANT)
Procedure: Use a 1/4” nut driver and 3/8”. Rotate governor
shaft counter clockwise until it stops (do not force). Tighten
governor arm lock with 3/8” wrench.
Step 22: Insert Spark Plug
Step 23: Replace Blower Housing
Note: Linkage plate flange mounts with the blower housing
top. Weave the blower housing over, under, and over.
Step 24: Replace Muffler
Note: Include gasket. #30 star
tool required. Replace muffler
guard. One bolt at rear of
muffler and four screws at
front.
Step 25: Replace Fuel Tank
Note: Replace fuel line. Four bolts front and back.
Step 26: Replace Throttle & Fuel Valve
Cover Plate
Note: Fuel valve must be in off position. Throttle must be at half.
Step 27: Replace Air Cleaner
Mounting Plate
& Gasket
Filter & Cover
Steps 28-29:
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Fill Crankcase with clean oil.
Fill fuel tank 1/3 full with gasoline.
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Be sure to add gasoline, not any other fuels.
Step 30: Start and Run Engine
Reminder: Only
while instructor
is present. Use
engine stand
and vice.
Turn run switch “ON” and set throttle to 1/2. No starting
fluid should be needed.
Step 31: Adjust Carburetor & Take
Let engine operate for approx. 5 min.
Measurements
Temperature
Readings
Full Throttle RPM &
Carburetor Adjustment
Step 32: Remove Fuel & Lubricant
Place fuel and lubricant into their appropriate containers.
Reassembly Wrap-Up
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Place a piece of tape on your engine that has your
name as well as a report of how the engine ran.
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Return engine to storage area.
Inventory and clean all tools in your assigned box.
Clean and return your engine storage bin to its
storage area.
Clean and straighten your area.