ENGINE SHOP REBUILD & SERVICE PARTS MANUAL - Jacobsen

ENGINE DISASSEMBLY
C. To remove a bearing, turn the crankcase on its side,
PTO (clutch) side up, and gently tap the bearing out
with a brass drift (DETAIL A). Discard the bearing.
The bearings can also be removed by heating the
crankcase to 200°+ Fahrenheit. This will expand the
aluminum crankcase and release the bearings.
Crankcase must be heated evenly in an oven. DO
NOT USE DIRECT HEAT, FLAME OR HOT LIQUID.
Remove the PCV Valve
(See Fig. B-4 “Balancer Shaft Bearing, Crankshaft Bearing and PCV
Valve” on page B-7)
It may be necessary to gently pry the valve
cover and valve free before they can be
removed from the crankcase.
A. Using a 10mm socket, remove two (2) bolts (ITEM 3).
(Later models have four (4) bolts)
B. Remove the PCV cover, valve, gaskets and hose
(ITEMS 4 - 10).
Disassemble the Crankcase End Cover
(See Fig. B-1 “Engine Components” on page B-4)
A. Using a seal puller, remove the crankshaft seal
(ITEM 2) from the fan side of the cover (ITEM 1).
(DETAIL A)
B. Remove the oil pump check valve from the engine
side of the cover.
1. Using a 10mm socket, remove the bolt (ITEM 3)
and check valve cover (ITEM 4).
2. Remove the spring (ITEM 5) and check ball (ITEM
6).
C. Clean and inspect the crankshaft bearing (ITEM 7)
and the balancer shaft bearing (ITEM 8) for damage.
If there is any doubt about a bearing, remove it.
1. If a bearing is to be removed, tap it out with a
brass drift and discard or use an oven to evenly
heat the end cover to 200° + Fahrenheit. This will
expand the aluminum cover and release the bearings.
Crankcase must be heated evenly in an
oven. DO NOT USE DIRECT HEAT, FLAME OR
HOT LIQUID.
Remove the Piston From Connecting Rod
(See Fig. B-1 “Engine Components” on page B-4)
A. Remove two (2) wrist pin retaining clips (ITEM 3).
1. Insert a small flat blade screwdriver into one of the
slots as shown. Push in and up to dislodge the clip
from the connecting rod (ITEM 2). (DETAIL A)
B. Remove the wrist pin (ITEM 4).
1. Use a suitable mandrel to carefully push the wrist
pin out of the piston (ITEM 1). (DETAIL B)
C. Remove the piston rings (ITEMS 5, 6, and 7).
Removal of Crankshaft Bearing
(See Fig. B-1 “Engine Components” on page B-4)
A. If the bearing (ITEM 1) is to be removed from the
crankshaft, use a mechanical press or bearing puller
to remove it. Discard bearing. (DETAIL B)
Engine Shop Rebuild and Parts Manual
Page B-3