DeWalt DW168F - SPEED;GOVERNOR Adjustment; Ignition Test; Oil Alert Test; START Mechanism

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
PROBLEM CAUSE SOLUTION
Excessive vibration/
knocking
Loose/worn connecting rod Repair connecting rod
Carbon in combustion
chamber
Clean carbon from chamber
Bentcrankshaft Disassemblecrankcaseand
repair
Engine mount damaged Checkenginemountingbolts
or replace rubber isolator
Timing out Checkflywheelkey

SPEED/GOVERNOR ADJUSTMENT
If speeds are out of adjustment use this procedure to reset to factory settings.
 1.Back off both idle adjustment screws far enough so they are out of the way.
NOTE: Thisistheblackplasticscrew(L3,Q2)atcarburetorandthescrewwiththe
blackspringundertheheadonthesolenoidL-shapedlinkage(ifequipped).
C5
E5, Q5
F2
L3, Q2
N5, Z4
 2.Loosenthegovernorarm(E5,Q5)fromtheshaft(F2)comingoutofthetopofengine.
On 9 and 13 HP engines:
Rotate the shaft counterclockwise with the governor arm held to the right at WOT
(wideopenthrottle).Makesuregovernor armremainsstraightanddoesnotpivotat
thejointin the middle(ifequipped). Retighten governorarmto shaft inthisextreme
position.
On 6.5 HP engines:
Rotate the shaft clockwise with the governor arm held to the right at WOT (wide open
throttle).Retightengovernorarmtoshaftinthisextremeposition.
 3.Governorspring(largesilver)shouldbeintheholeonthegovernorarmclosesttothe
shaft.
 4.Backouthighspeedadjustmentscrew(N5,Z4)ontopoftheengineatthesmallsilver
lever. A few complete turns will do.
 5.Starttheengine.Ifithunts(speedvariesupanddown.),movethegovernorspringto
theouterhole,ifpoweristoolowmoveitbackintowardtheshaft.NOTE: Hunting is
unpredictable and sometimes the opposite movement of the spring helps.
6. Engine will probably be running slow. Adjust high speed to 3600 rpm by turning high
speedscrew(N5,Z4)ontop,intoincreasespeedandouttoslowdown.Ifenginestill
runs to fast, governor arm may still be out of adjustment on shaft or it has moved since
tightening.Ortherecouldbeaninternalgovernorissue(thisisrare).
NOTE: If governor arm was over tightened to shaft and has no gap at the end of the
arm next to the shaft, over tightening of the governor arm will not result in sufficient
holding force to shaft. The governor arm must be replaced.
 7.Withengineoff,ensureidlelinkagesonsolenoidarenotbindingandarefreetomove
thefulltravel.Alsomakesurethrottlelinkagefromcarburetortogovernorarmmoves
backandforthfreely.
 8.Ensuretheidlescrew(withblackspringundertheheadontheL-shapedleveronthe
solenoid) isbacked outfarenoughtojustclear touchingthegovernorarmwithidle
control turned off.
9. Start the engine. Turn idle control on after engine has warmed up some. Solenoid
shouldpushgovernorarmandthrottletothelefttowardcarburetorandtheblackplastic
throttleshouldstopupagainstblackplasticscrew(L3,Q2).Adjusttheidlespeedto
2700–2800RPMbyadjustingthisscrewintoincreaseidlespeed,backitouttoreduce.
Ifsolenoiddoesnotpushleveroverfarenoughtotouchblackplasticscrew(thescrew
withthe blackspring onthe L-shaped solenoid lever) canbe turned into makethis
happen. Both of these screws can be adjusted in our out so one is not at the extreme
of it's adjustment length.
10.Cycleidlecontrolswitchonandoffafewtimesandcheckbothhighspeedandidle
speed to ensure they are still correct.
IGNITION TEST
CHECK FOR SPARK
WARNING: Risk of explosion. Spilled gas o line and it’s vapors can be come ignited from
sparks from smoking products, electrical arcing, exhaust, flame, gas es and hot engine com-
ponents such as the muffler.
Make sure there are no sources of ignition, such as smoking
products near servicing location. Wipe any fuel spillage from engine.
WARNING:
 • Neverholdthesparkplugwirewithwethandswhileperformingtest.
 • Wipeanyfuelspillagefromengine.
 • Makesurethesparkplugisnotwetwithfuel.
 • Donotallowsparksneartheplughole.
 1.Removethesparkplugfromthecylinderhead.
 2.Groundsparkplugagainstairshroudasshown.
3. Place the on/off switch in the “ON” position and
cranktheengine.
 4.Check to see if the spark bridges the electrode
gap.Ifyoucanseethespark(thismaybedifficult
inbrightdaylight)theproblemismostlikelynottheignitionsystem.Ifsparkplugfails
tospark,seeFlywheel Ignition Inspection.
OIL ALERT TEST
Perform this check if the engine will not start and other troubleshooting attempts
have failed. Ensure oil is a proper level, see Oil under Maintenance.
Engine will not start:
Disconnect the lead from the oil alert
sensor and directly connect the
leads from the ignition switch and
the ignition bypassing the low oil
sensor. If the engine starts replace
the sensor.
Engine will not stop:
With the engine running disconnect
the oil alert sensor lead and ground
it against the engine. If the engine does not stop replace the sensor.