Small Engine Disassembly A Visual Guide

Objectives: Disassemble 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: Follow the disassembly steps precisely. Be sure to reference notes and sketches you created during engine disassembly. Your engine may not be exactly like the engine in this presentation. Four different engine types are used in the laboratory in order to expose students to variations in engine design.

TOOL TOOLS – 5/16” socket, 3/8” socket, ratchet wrench, extension, inch pound torque wrench, newspaper, oil can, piston ring compressor and small hammer.

Step 1: Remove Spark Plug

Step 2: Check for “Spark” Using an ignition tester check for( spark. Use your spark plug) Attach the tester to the spark plug wire and then ground the tester. Hold the engine’s blower housing on the engine and pull the rope in order to check the engine’s ignition system. Must show spark to instructor before proceeding.

Step 3: Remove Blower Housing

Step 4: draw a picture of Carburetor, and Linkage Remove S Linkage Before removing Carburetor Reminder: drawing your carburetor and linkage. .

Step 5: Remove Carburetor, and Linkage Carburetor Assembled Linkage Assembled Kill Wire Attachment

Step 6: Remove Washer, Starter Clutch, & Flywheel Screen –OR- Flywheel Screen, Bell Housing, & Crankshaft Nut

Step 7: Remove Flywheel and Flywheel Key Reminder: Remove any oxidation from the key, key way, and/or flywheel magnets.

Step 8# Remove points cover

Steps 8-10#: 8 Remove Breaker Point and Condenser Cover 9 Remove Breaker Points and Condenser. Reminder: Draw a picture of points and condenser. 10 Remove Plunger

Step 11#Remove the coil and condenser together as a assembly.

Step 7: Remove Washer, Starter Clutch, & Flywheel Screen –OR- Flywheel Screen, Bell Housing, & Crankshaft Nut Reminder: Washer convex side up. Engines will have a bell housing, screen and crankshaft nut.

*Note: If engine is equipped with Magnetron® Ignition System, disregard steps 6-8. If not, refer back to your disassembly sketch. No point and condenser assembly

Step 11-b: Remove Muffler Reminder: Use a screw drive and dead blow hammer.

Step 12: Remove Cylinder Head, Head Gasket, and Corresponding Parts Shield 3 Long Bolts Reminder: Note the location of the long bolts

Step 13: Remove Valve Cover Plate Reminder: The plate has a gasket. Use a 1\4 nut drive to remove machine bolt.

Step 14: Remove of valves Rotate the crankshaft clockwise (as viewed from the flywheel side of the engine) until the piston is at TDC at the end of the compression stroke. Make sure that you have your engine on clean newspaper!  

Step 15: Remove the Valve Springs and Retainers Keepers

Step 16: Remove the Valve Springs and Retainers Reminder: Use valve spring compressor tool. Don’t forget to remove the valve keeper properly. The heavier gauge or taller spring goes to the exhaust valve.

Step 17: Remove Crankcase Cover Using the 7/16” socket remove the bolts that secure the crankcase cover to the block. Carefully remove the cover using your hands and fingers. DO NOT pry off the cover with a screwdriver or any other object!

TURN THE BLOCK UPSIDE DOWN!

Step 18: Remove Cam Gear Rotate the crankshaft until the timing mark on the camshaft gear lines up with the timing mark on the crankshaft. Note the position and character of these marks and draw a diagram of the cam and crank with the timing marks. .

Draw a DIAGRAM of Camshaft timming marks

Step 19: Remove Tappets

Now rotate the crankshaft until the piston is at BDC Now rotate the crankshaft until the piston is at BDC. Remove the rod cap bolts using the 7/16” socket. NOTE: do not get these bolts mixed up with the crankcase cover bolts! These bolts have a fine thread, the cover bolts have a course thread! Remove the rod cap and oil dipper. Note the position of the oil dipper, also note which direction the open end of the rod is facing.

Step 20: Remove Connecting Rod Cap Reminder: Draw a picture of the rod. Remove cap and rod in the bolts these bolts are fine thread. .

Step 21: Remove the Piston and Connecting Rod from the Cylinder Look what direction the piston & rod is coming out of the cylinder

Steps 22: Remove the Crankshaft

STEP 23 Stop NOW USE THE TEXT BOOK TO IDENTIFY EACH ONE OF THE PARTS BEFORE YOU ON YOUR WORK TABLE. KNOW THESE PARTS! YOU WILL BE REQUIRED TO IDENTIFY THEM ON AT TEST!  

Step 11: Remove the ignition coil and Governor Blade