Yanmar 1GM User Manual page 46

40
from a pic kup loca ted in the oil pan , then forces o il 10 the
necessary eng ine components. The o il pum p is dri ven by
the crankshaft gear .
An oil pressure relief valve regulates oil pressure at
300-400 kPa (43-57 psi). When oil pressure exceeds the
desired pressure, the relief va lve opens and expels oi l into
the liming gearcase . A low oi l pressure warning light on
the instrument panel and a warn ing ala rm buzzer act ivate
if oil pressure is below 9.8 kPa (IA psi).
Refer
to
Chapters Five . Six and Nine fo r se rvice proce-
dures.
Oil Pressure Test
The engine is equipped with an oil pressure warnin g '
light and alarm thai
arc activated if
low oil pressure oc-
curs. To verify low oil pressure , pcrfonn the follo wing oil
pressu re test.
I. Disconnect the wi re lead from the oil pressure sender
( Fi ~ u re
lJ, typical).
CHAPTER TWO
2. Remove the oil pressure sender.
3.
Connect a suitable oil pressure gauge.
4. Start the engi ne and
note
the oil pressure reading at idle
and wide open throttle .
5. Com pare the gauge read ings with the spee ilicat ions in
Table 3 .
Table 1 ENGINE TROUBLESHOOTING
Trouble
Engine cr anks slo wly
Eng ine will not crank
Engine will not start
Engine sto ps s uddenly
Probable cau. .
Battery fa ulty or ~w c harge
Faulty starter motor
Incorrect engine 011 viscosity
Discharged battery
Corroded battery termin als
loose connection In start ing ci rcuit
Defective starting sw itch
Starting motor brushes dirty
Jammed starter drive gear
Faulty starter molor
Seized engine
Empty fuel tank
Dirty or plugged tuer fllter
Air In injection lines
Faulty fuel feed pump
Faulty tuel lnJec:tlon pu mp
Faulty go vernor
Mlsadju sted co ntr ols
Im proper l uel injectIon timing
Poor v alve seating
Damaged cylinde r head gas ket
Worn or broken p ist on ring s
Empty fu el tan k
Air in fue l lines
(continued)
Correction
Charge o r replace battery
Repair 01" replace sta rter motor
Repl ace wi th proper engine oil
Ch arge o r rep lace batt ery
Clean terminals
Clean and ti
ghten all co nnect ions
Repla ce swi tc h
Cle an o r repl ace bru eh ee
loosen start er motor to Iree gear
Repla ce motor
Inspect and rep air
Fill tan k w ith pro per l uel
Clean fu ellilt ers
Bleed air In Injec tio n lines
Repa ir fue l feed pu mp
Repair l uel Injec:tlo n pump
Repair govern or
Ad ju st speed and stop co ntrols
Ad ju st fuel injectio n liming
Check 101" broken 01" _ak valve springs,
wa rped stem s, carbon and g um deposits
and insuffic ient tappet clea rance
Check 101" lea ks arou nd gask et w hen
engi ne Is c ran ked; if a leak is fou nd,
replace gasket
Repl ac e worn or b rOken ri ngs ; c hec k
cy li nde r s for out-of-rou nd and taper
Fill l uel ta nk
Bleed fu el li nes