Wisconsin 191R Assembly instructions

ENGINE MODELS
191 R ·192R ·193R· 200R
INSTRUCTIONS FOR ASSEMBLY AND DISASSEMBLY
(lntructions pour le Montage et Demontage du Moteur)
ISSUE MM· 323
... . ..
WISCONSIN
r:Ji WISCONSIN- HIRTH Snowmobile and Vehicle Engines
MOTOR

Technical Data
Enginft Output:
Direction of rotation:
Bore:
Stroke:
Type
191 R ...
19 hp (DIN)
at 5500 rev/min
192 R ...
20.5 hp (D I N)
at 5750 rev/min
counter clockwi!le, viewed towards P.T.O.
2.953" (75 mm) 3.031" (77 mm)
2.68" (68 mm) 2.68'· (68 mm)
193 R ... 200 R ...
19 hp (DIN) 23 hp (DIN)
at 5000 rev/min at 5250 re
v/ min
2.913" (74 mm) 3.169" (80.5 mm)
2.68" (68 mm) 2.87" (73 mm)
Piston displacement: 18.3 cu. in. (300 cc.) 19.34
cu . in. (317 cc.) 17.82 cu. in. (292 cc.) 22.7" (372
cc.)
Point gap: .016 ± .002"
(0.4.:!:0.05 mm)
Ignition timing: Retarded: 4 t 3° BTDC
= .004 I·.0085"
(0.1 +0.22 mm)
Spark plug
Advanced: 22+ 3 1) BTDC
= .122 +. 035"
(3.1 -+- 0.9 mm)
for normal operation: M 225 T 1 Bosch
for heavy-duty operation: M 225 T 1 Bosch
.016::::: .002"
(0.4±0.05 mm)
4+ 3 BTDC
= .004+.0085"
(0.1 '1- 0.22 mm)
22-:-3 :. BTDC
-.122 +. 035"
(3.1 +0.9 mm)
M 225 T 1 Bosch
M 225 T 1 Bosch
.016 ± .002"
(0.4±0.05 mm)
4+ 3° BTDC
.004+ .0085"
(0.1 +0.22 mm)
22+3 -> BTDC
=.122 .035"
(3.1+0.9 mm)
M 225 T 1 Bosch
M 225 T 1 Bosch
.016 ± .002"
(0.4::!:0.05 mm)
4+3 ° BTDC
.0043+ .009"
(0.1 1 +0.23 mm)
22+3 BTDC
- .13+.039"
(3.3+ 1.0 mm)
M 225 T 1 Bosch
M 240 T 1 Bosch
Spark plug gap: .02+.004" (0.5·1
0.1 mm) .02 -1 .004" (0.5+0.1 mm) .02+.004" (0.5 0.1 mm) .02 f-.004" (0.5 +0. 1 mm)
Ignition system: Bosch dynamo magneto i gnition with automatic advanced timing
light power 40 Watt , 12 Vo lt or 75 Wa tt, 12 Volt
f

Disassembly of motor
Remove motor from apparatus. Attached parts, like
muffler, carburettor, electric starter must be removed.
2. Screw assembly angle W 115 to tho drill holes of the
base and
clamp motor with angle into the vice.
Fanhousing
3. Lift off fanhousing after loosening the 4 hollow
screws.
F
lyw heel
4. Screw holding device W 116 f or the flywheel to the
crankcase.
Typ e 200 R: Assemble holding device as shown in
frg. 2. Take for the top attachment pomt 1 ellern screw
with spring washer of the blind flange or the electric
starter.
Type 192 R: First take off ignition coil, then the hol-
ding device can be attached,as shown in fig. 1.
Types 191 R and 193 R: Fasten holding device as
shown in fig. 1. Ta ke off catch with locking plate after
loosening
the 3 ell ern screws with wrench 5 DIN 911.
Take
off the cover plate lieing behind the catch.
5. loosen hexagonal nut with which the flywheel is fa-
stened with hexa,gonal wrench. W id th of wrench .9449"
(24 mm) (SW 24). Fasten removal device W 113 with
the 3 hexagonal screws in the three threads of the
flywheel. loosen flywheel by turning the pressing
Demontage du moteur
Depose du moteur, depose des accessoires tels que,
carburateur, silencieux d'echappement, demarreur
electnque.
2. Fixer le gabari W 115 aux trous do fixation du socle,
le serrer dans l'ctau.
Capot de ve ntilateur
3. Demontcr le capo! de de ventilateur avec le lanceur
a main premonte en devissant les 4 vis a six pans
creux.
Ve ntilat eur
4 Visser le drspositif de blocage du ventilateur W 1 16
sur le carter du moteur.
Mot eur type 200 R manter le dispositif de bl ocage du
ventilateur comme
indique fig 2. Pour le point de
fixation superieur, so servir d'une vis a six pans creux
servant au montage du demarreur
ou du 1 /t carter.
Moteur type 192 R demonter prealablement Ia bobine
d'allumage, puis fixer le dispositif de blocage du
ventilateur (voir Fig. 1).
Moteur type 191 R
Moteur type 193 R fixer le dispositif de blocage du
ventilateur
et comme indique fig. 1, devisser les
trois vrs a six pans creux au moyen de Ia cle 5 DIN
911, enlever, l'entrainer et Ia tOle de protection se
trouvant
derr i ere lui.
5. Devisser l'ecrou a six pans fixant le ventilateur au
moyen
de Ia cle plate de 24 mm, puis visser l'extrac-
teur W 113. Visser les trois boulons de l'ex tracteur
dans les trois trous prevus a cet effet au ventilateur.
Arracher le ve ntilateur en tournant Ia vis de pression

screw of dev i ce W 113 towards tho right side. Un-
screw holding device so that the flywheel can be
taken
off.
Igniti on
6. Take off sparkplug hood for spa rkplug and screw out
sparkplug.
1
91 R and 193 R: Loosen fastening clamp of ignition
wire.
192
Rand 200 R: Loosen the 2 tapping screws with
which
the coil is fastened, if the coil
was not removed before. Pull blue
generator cable out of the plug con·
nection with the coil. Best cut off
plug fr om the gener ator wire and pull
off protection sleeve. Pull generator
cable through the upper rubbei
socket in the housing. A drop of oi l
in the r
ubber sockets makes the pul-
ling through of the cables easier.
In all type s of motors loosen the 3 fastening screws
with which the armature plate is screwed to the
housing. Take
off the armature plate when doing this
also pull out the wires.
Cylind
er
7. 191 Rand 193 R: Loosen tapping screws with which
air
guide plate is fastened. Take off
airguide plate by pulling it upward.
Loosen screws
or nuts with which
the cyli
nder head is fastened. Take
off cylinder head with head gasket.
200 R: Unscrew the 4 hexagonal nuts with
which tho cyl
inder is screwed to the
crankcase. Use wrench
SW 17. Lift
off cylinder.
Pi ston
8. Remove safet ies of gudgeon pin.
Press out gudgeon pin with assembly pin.
Assembly
pin 200 R: W 39 / 6
" 191 R
" 192 R Iw39' 4
• " 193 R I
If necessary slightly tap with a hammer, while dotng
this hold piston with hand. Remove piston.
9. Push needle cage out of the small eye of the con-
necting rod. To keep it , best place it over the gud-
geon pin.
Oil seal
10. Turn motor in vice at 180 .
11. Make a hole in the covenng of the oil seal with a poin-
ted tool. In doing so pay attention that the bearing
lieing behind the covering, is not damaged. Then put
a hook into the hole and pull out the oil seal.
Cran kcase
12. Remove the exterior snap ring on the crankshaft with
exterior snap ring pliers. With ellern wrench screw
5 DlN 911 loosen the six screws with which crankcase
and crankcase flange
are screwed together.
2
de l'extracteur dans le sens des aiguilles d'une
montre. Devisser le
dispositif de blocage afin de
pouvoir retirer le ventilateur.
6. A ll umage
Retirer le chapeau de Ia bougie et devisser Ia bougie.
191 Ret 193 R: Enlever Ia bride de fixation du fil de
bougie.
192
Ret 200 R: Devfsser les de ux vis tara ud fixant Ia
bobine, a moins que cette derniere
n'ait eta enlevee prealablement.
Retirer le fil bleu de Ia prise dans Ia
bobine, couper Ia languette de con-
tact , sortir le manchon par e-p luie, re-
tirer le fil du caoutchouc passe, cable
une goutte d'huile facil itera !' opera-
tion.
Concerne tous les moteurs: Devisser l es 3 vis fixant
le plateau porte induits sortir le plateau avec les fils
des conduites electriques .
Cylindre
7. 191 Ret 193 R: Devisser Ia vis taraud fixant le capot
guide d'air, retirer ce de r nier vers
le haul.Devisserles ecrous ou les vis de
fixation de Ia culasse retirer Ia culasse
200R :
P is ton
ainsi que
le joint de culasse.
Devisser les 4 ecrous asix pans fixant
le
cylindre au carter au moyen de Ia
cle plate de 17 mm. Deposer le cylin-
dre.
8. Retirer Jes jones d'arrAt de l'axe de piston.
Sortir J'axe de piston au moyen de Ia broche specialc.
Broche- 200 R: W 39 /6
Broche -191 R: 1
Broche ~ 192 R: Jl
Broche -193 R:
W39 /4
Au besoin maintenir le piston d'une main et en don-
nant des petits coups de marteau faciliter !'extraction.
Enlever le piston.
9. Retirer le cage a aiguilles de l' oeil du pied de bielle.
Pour plus
de surete,if est preferable de Ia remettre de
suite sur l'axe de piston.
B
ag ue d'etancheite
10. Faire pi voter le moteur de 180° dans l'etau.
11 . A l'aide d'un pointeau, en veillant 'ane pas abimer Je
roulement, percer un trou dans Ia bague d'etancheit e.
Puis au moyen d'un crochet passe par ce trou. Retirer
Ia bague d'etancheite.
Cart er
12. Enlever Je circlips de l'axe du vilebrequi n au moyen
d'une
pince a circlips exterieurs. Devisser les vis asix
pans creux au moyen
de Ia cle male a six pans
5 DIN 911.
..

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13. Screw removal device W 119 to the crankcase flange.
Put pressure part W 105/4 into the boring of the
crankshaft and by turning the pressure
screw press
crankcase with crankshaft away
from the crankcase
flange. After this remove device W 119 (fig. 3).
Crankshaft
14. The removal of the crankshaft from the crankcase i:;
done in the following way: Heat ·the crankcase on the
ignition side
to 212 ° to utmost 285 ° F (100-140 °
centigrades). Best use a blow forch for it (fig. 4).
3
13. Visser le dispositif de demontage du vilebrequin
W 119 sur le carter. Poser Ia piece d'appui W 105/4
dans le creux de l'axe du vilebrequin, serrer Ia vis de
pression extraire le vilebrequin tout en separant les
1/ 2 carters. Fig.
3.
(3)
Vilebrequin
14. Sortir le vilebrequin du 1/t carter en procedant comme
suit:
Chauffer le carter c6te volant magnetique a 212 °
maximum 285° F {100-140 ° C). Se servir de prefe-
rence d'une lampe asouder. Fig. 4.
(4)

Hold crankcase and crankshaft and knock out crank-
shaft by tapping with a rubber hammer. Pay attention
that the cranshaft does not drop to the floor (fig. 5).
15. Knock
out the oil seal on the ignition side with a pin
and hammer.
Ball bearing
16. Remove snap ring from the inner side of the crank·
case flange with snap ring pliers. Heat flange as
described in paragraph 14. After this push out ball
bearing, e.g. with a hammer handle.
17. Remove the ball bearing placed on the ignition side
of the crankshaft with tool W 107 and insets W 107/15
(fig. 6).
4
Maintenir carter et vilebrequin; par des petits coups
de maillet en caoutchouce sortir le vilebrequin. Veil -
ler a ce qu'il ne tombe aterre. Fig. 5.
{5)
15. Enlever Ia bague d'etancheite de son logement dans
le carter au moyen d'une broche et d'un marteau.
16. Roulement abilles
Retirer le circlips de l' interieur du flasque du carter
au moyen d'une pince a circlips interi eurs. Chauffer
le carter comma decrit paragraphe 14. Puis a l'aide
d'un manche a marteau, par exemple chasser le rou-
lement vers l'exterieur.
17. Extraire le roulement cote volant magnetique au
moyen
de l'extracteur W 107 et accessoire W 10 7/15.
Fig. 6.
(6)

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18. Clean parts of motor with washing gasoline. Carefully
scrape off all residues of packing material on the
sealing surface.
19. Replace defective parts.
Motor assembly
Ball beari ng
1. Place snap ring into the P.T.O. side of the crankcase
flange.
Heat flange to about 212 to at the utmost
285 " F (100-140 ° centigrades). Press in ball bearing
from the inside until
it touches the snap ring. Install
$CCond snap ring.
2. Screw crankcase flange to assembly angle W 115 and
put it into vice (fig . 7).
Cr ankshaft
3. Push crankshaft with pivot on the P.T.O. side through
the bearing. Screw pin of the tool W 112 into the
internal thread
of the crankshaft. Push feeding-in too l
W
112 over the pin until it touches the ball bearing.
After this retract the tool as far as H is necessary to
push the peg through tool and pin. Pull crankshaft by
means of the two levers of the tool to the end of the
stroke of the device. Then put the pin into the next
hole in the direction towards the flange and repeat
this action until crankweb touches the bearing. During
the
whole action pay attention that the connecting
rod is standing straight upright, since otherwise it
may be bent (see fig. '7).
4. Screw
off tool W 112 and install snap ring on the
crankshaft on the P.T.O. side.
5. Slightly oil radial seal on exterior and interior dia-
meter and push it towards the bearing. Press the
5
18 . Nettoyer toutes les pieces du moteur a !'essence.
Enlever soigneusement les restes
de joints ou de
pate d'etancheite sur Ia surface des joints.
19. Toute piece detectueuse est a remplacer.
Remontage du moteur
Roulement abilles
1. Remonter le circlips dans Ia bride du
1
/~ carter cOte
prise de force. Chauffer le 1/ 2 carter a environ 212°
max. 285 ° F (100-140 ° C).
Monter le roulement dans son logement jusqu'a ce
qu'il vienne buter contre le circlips. Monter le 2e
circlips.
2. Visser le ' 1/ 2 carter sur le gabari W 115 le serrer dans
l'etau. Fig. 7.
(7)
Vilebrequin
3. Passer le bout d'arbre de fa prise de force dans Ia
bague interieure du roulement. Visser l'appareil de
montage W 112 dans le pas de vis du vifebrequin,
pousser l'appareil de montage jusqu'a
ce qu'if vienne
buter contre le roulement, puis revenir en arriere de
fac;on a pouvoir passer Ia cheville dans le trou de
l'appareil de montage et celui correspondant de l'axe.
A !'aide
des deux leviers introduire le vilebrequin
jusqu'a fin de course de l'appareil. Enlever Ia cheville
et Ia replacer dans le trou suivant; continuer le pro-
cessus de montage jusqu'a ce que le vilebrequin vien-
ne
buter contre le roulement a billes. Ce faisant veil-
ler constamment a ce que Ia bielle soit orientee ver-
ticalement vers le haut, si non elle risque d'etre en-
dommagee. Fig. 7.
4. Enlever l'appareil de montage W 112 et mettre le
circlips en place sur l'arbre cOte ptise de force.
5. Huiler legerement Ia portae interieure et exterieure
de Ia bague d'etancheite Ia pousser contre le roule-

radial seal with pressure disk W 37 t8 and tool W 112
until it touches the snap ring. The forcing in is done
as described in paragraph 3 (fig. 8).
Cr•nkcase
6. Turn crankcase flange in the vice 180° around.
7. Put sealing material on the sealing surface on the
crankshaft flange.
8. Heat up the half of the crankcase lying towards the
Ignition to 212 to at the utmost 285 ° F (10Q-140°
centigrades) and then put on the flange. Pay atten-
tion to the fitting pins. Push the second ball bearing
on the crankshaft and push
it with tool W 112 to the
collar on the crankshaft (for action see paragraph 3)r
Take
off device and place snap rmg into the hou-
sing (fig. 9.).
ment. Puis au moyen
de Ia plaque W 37/8 et de
l'appareil de montage W 112. Presser Ia bague
d'etancheite dans son logement jusqu'a ce qu'elle
vienne buter contre le fond, suivre le processus de
montage decrit. Paragraphe 3 (Fig. 8).
(8}
Carter
6. Faire pivoter le 1 /! carter de 180° et reserrer le gabari
dans l'etau.
7. Enduire toute Ia surface de jointure du carter d'une
solution d'etancheite.
8. Chauffer le
1/!
carter cOte allumage a 212-285 ° F
(10Q-140° C). Puis le mettre en place sur le
1/!
car-
ter oppose, en veillant aux gousons-guides. Monter
le 2e roulement sur le vilebrequin et a l'aide de l'ap-
pareil de montage W 112. Pousser le roulement
jusqu'a Ia collerette du vilebrequin (processus de
montage
voir paragraphe 3).
Devisser
l'appreil de montage W 112, mettre le
circlips en place sur l'arbre. Fig. 9.
(9)
4

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9. Oil radial seal. Push it with
sealing
lip to bearmg over
assembly socket W 1 H. Af-
ter this put in radial seal
with tool W 112 and pres-
sure plate W 37 /8 (fig. 10).
10. Screw together crankcase
and crankcase flange with
6 ellern screws.
Attention: Always put new
flat washers under the he-
xagon nuts so that the
crankcase is
satisfactorily
sealed. Tighten screws with
6.5 •1•5 ftlbs (0.9·0·2 kpm).
Piston
11. Put on cyinder base gasket. Push needle c~ge mto
the small eye of the connecting rod. Oil connecting
rod bearing and needle cage with good motor oil. Put
in snap ring for gudgeon pin pointing towards the
ignition. On the top of the piston an arrow is marked,
pointing in the direction of the exhaust. By this the
correct position of the piston can be found at any
time. Put piston
over the small eye of the connecting
rod and push gudgeon
pin with assembling pin until it
touches snap ring. (Fitting assembling pins see
disassembly
of motor, paragraph 8) . Install the second
snap ring (fig. 11 ).
7
Piston
9. Huiler Ia bague d'etanchei-
te, Ia passer par dessus Ia
douille de montage W 114,
Ia levre d'tHancheite, tour-
nee vers le roulement, puis
a l'aide de Ia plaque W 37/8
et au moyen de l'appareil
de montage W 112, Ia mett-
re en place. Fig. 10.
10. Visser le 1/t carter a flasque
sur le '/!
carter au moyen
de 6 vis a stx pans creux.
Attenti on : Se servir de ron-
dalles joints neuves pour
etre assure d'avoir une
etancheite parfaite.
Sorrer les vis a 6,5 ·'·5 ftlb
(0,9+0 ·2 kpm).
11. Poser le joint de Ia base du cylindre , passer Ia douille
a aigutlles dans l'oeil du pied de bielle. Huiler avec
une bonne
huile le roulement de Ia tete de bielle,
ainsi que Ia douille a aiguilles. Monter le jonc d'arret
de l'axe de piston cOte volant magntHique. l'axe de
piston porte une fleche qui devra toujours !Hre orien-
tee vers !'admission ainsi Ia bonne position du piston
est facilement controlable a tout moment.
Passer
le piston sur le pied de bielle et a !'aide de Ia
broche de montage pousser l'axe de piston jusqu'a ce
qu'il vienna buter contra le jonc d'arret d'axe. Broche
de montage appropriee. Voir demontage du moteur.
Point 8).
Monter le deuxieme jonc d'arret d'axe. Fig. 11 .
(11)

Cautiona lly clean carbonised piston ring grooves. Best
use for it a piece of a piston ring ground down on
one side.
Cylinder and cylinder head
12. Push wooden piston support W 24 under the piston.
Oil piston skirt and cylinder bore with motor oil. Turn
piston rings
by hand in such a way that the rings are
lieing between the guard pins. Press together rings
with piston ring pliers W 108 and clamping collar.
Necessary piston ring clamping collars
191 Rand 193 R: W 108/15
192
R: W 108/16
200 R: W 108'17
Push cylinder over p•ston, in doing so pay attention,
that the arrow on the piston head points toward the
exhaust passage
of the cylinder (fig. 12).
13.
200 R: Tighten down cylinder with 4 washers and nuts
crosswise
with a fork wrench SW 17 with 33•3 ftlbs
(4.6.0 •kpm). Put cylinder head gasket in place and
put on cylinder head. Tighten cylinder head with
8 ellern screws and washers with hexagonal spanner
6 DIN 911, 16.5+
0•2
ft lbs (2.3•0•3 kpm).
191, 192
and 193 R: Put cylinder head gasket in place
and put on cylinder head. Tighten down cylinder and
cylinder head crosswise with 4 washers and nuts
19.5•2 ftlbs = 2.7•0•3 kpm.
Attention: Always repl ace cylinder head gasket in
order to avoid gas blow of the cylinder head! When
cylinder head is put on pay attention that the fins are
parallel
to the axis of the crankshaft.
Au cas ou les rainures des segments seraient cala-
minees, les nettoyer avec precaution. Le mieux est
d'utiliser un morceau de segment rectifie a Ia meule
a l'une de ses extremites.
Cylindre et culasse
12. Placer le piston sur le support en bois W 24. Huiler
les parois du cylindre et le corps du piston.
Tourner les segments a Ia main pour faire corres-
pondre les ergots avec les goupilles des rainures du
piston.
Serrer les segments a l'aide de Ia pince a
segments. W 108.
Pinces asegments appropriees
191 Ret 193 R W 108/15
192 R W 108/16
200 R W 108/ 17
Passer le cylindre sur le piston, veille r a ce que Ia
fleche sur le fond du piston so
it 01 ientee vers le
t::anal d'aspiration. Fig. 12.
(12)
13. 200 R: Proceder par serrage en croix des 4 ecrous au
moyen de Ia cle plate de 17 (SW 17) serrer a33•3 ftlb
(4,6 o.• kpm). Mettre le joint de culasse en place,
monter Ia culasse, Ia serrer a l'aide des 8 vis asix
pans
creux au moyen de Ia cle 6 DIN 911. Serrer A
16,5•2
ftlb (2,3+0·
3 kpm).
191 , 192 et 193 R: Mettre le joint de culasse en place,
monter Ia culasse, serrer les 4 ecrous en procedant
par serrage en croix serrer. 19,5"2 ftlb (2,7.o·3 kpm).
Attent ion: Monter un joint de culasse neuf afin
d'eviter une perle de compression. Au montage de Ia
culasse veiller a ce que les ailettes de refroidisse-
ment soient paralleles a l'axe du vilebrequin.
,.
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INSTRUCTIONS FOR ENGINE PROTECTION
Under certam duty conditions present-day fuels leave harmful residues
(acids) in the engine. These residues may lead to senous corrosion and
heavy damage {corroded bearmgs) when the engine is shut sown for a
considerable penod. Enc•nes with low total running ttmes are particu-
larly liable to this trouble.
For thts reason HIRTH enganes are supplied wtth scavengtng oil after
the final tests. We strongly recommend to repeat these protective mea-
sures if it is likely that the engine will remain unused for some time
t after it was operated . In any case the engines shall be protected anew
after the operation season, that means before being laid up .
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For protection of the engine the following procedure is adopted:
1. Clean the engine at the outside.
2 Remove the spark plug.
3. Set the p1ston at bottom dead center. To do this the ptston head 1s
contacted with a screwdnvcr or s1mi lor tool through the spark plug
orihce and the engine is slowly turned over until the piston has
reached tts I owest pos1taon.
4. Introduce the funnel (part No. WS3) wtth the bent ptpe through the
spark plug orifice downwards along the cylinder wall unttl the end
of the ptpe enters clearly mto the transfer port (see sketch).
The two transfer ports are located at the front and rear of the cylinder;
the tnlet and exhaust ports arc located on the right and left-hand side.
5. Introduce mto each transfe• port through the funnel at least IS c. c.
(1/2 oz.) or scavenging oal. If scavengmg oil cannot be obtained it
may be replaced by one of the usual comme rcial brands of anti-cor-
rosion oil for two-stroke eng1nes.
6. After introducing the scavenging oil tum the engine over several
times by mod but do not start the engine.
7. During the stonng period tum the engine over every 4 - 6 weeks so
that all parts are re-wetted with scavenging oil.
Returning engine to service:
Clean the spark plug If wetted with scavenging oil. Close the starter throttle of the
Tillotson carburetor. Start engine normally. ln case the engine dies down, clean-
spark plug once more and repeat starting. Let the engine run until oil is burned up.
Suitable scavenging oils:
B P: BP Energol engine protecting oil
B V-A R A L: Arol engine protecting oil 20 W 20
ESSO: Rust-Bon 339
M0 B I L 0 I L: Mobil Kote 503
SHELL: Shell Ensi s Oil 20
These oils must not be mixed with gasoline but should be kept only for scavenging
the engine.
For runmng the engtne, always use a brand mark two-stroke oil with oxidation-
corrosion inhibitor.