Onan MJA Series Service Manual page 12

3,. 'THE ,;ENGI,NE
The generaHngplants in this manual use a 4·.strokecycle, vertical in.line, valve in h € a d,'
spark ignition, gasoline fueledengir,ewitha cooling system
Di
the pre'ssure 'circulatingliquid
cooled type.
in
au
.cases,l..hespeed is governor controlled at 1800 rpm for 60 cps output generating plants.
same manual'because
01
the
great similarity between them. Unl"ss otherwise .specified,
One, twO, and lour.cylinder generating planlsare included in
instructions and .procedUres
apply.LD one, two, and four cylinder·engines.
NOTE: All dimensions,clearances, and wear limits are inclu'ded in Sect 9,
ENGINE DATA
Model Series
Number cylinders (vertical in-line) ....... .
Displacement {cubic inch} ..........•.. , ..
Cylinder bore ..•....................•...
Piston Stroke ....................... , .. .
RPM {for .60
~ycle}
.............. , ...... .
Compression ratio 6.5 to
1
for gasoline
(uel ., ................ ' ............. .
Exhaust connection (pipe .tapped) ....... , ...
SteUite faced exhaust valve (s) .. , , ..... , ..
Valve ·rotators on intake
and
exhaust ......
Connecting· rod bearings arelri-rnetal
replaceable ............. " ... ,... ....
oMain bearings ·are leaded bronze; precision
type lor replacement {quantoity used) .....
Battery ignition .... , ............ , ......
Battery voltage lac plant) ... ,.. . .......
Battery size (ac plant):
,705
MJB ilOMJCIl5MJC
ISMJ8
yes
yes
yes
2
yes
12-v
4
4
60
2
2
120 120
3-1/4
60
3-1/4 3-1/4
3-5/8
3-1/4
3-5/6
1800
3-5/8
3-5/8
1600
1800 1800
yes yes
1-1/4
yes
yes
1-1/2
1-1/2
yes
1-1/4
yes
yes
yes yes
yes
yes yes
yes
yes yes
yes
3
yes
3 2
2
·yes
yes
'yes
12-v 12-v 12-v
12-v
two in
sertes
two in two in two in
series
105
.series.
series
165
105
105
SAEgroup 1H ....•....... , ..........
I
two in
series
Amp/hr.
SAE
20-br
(nominal) '" .... .
105
Water cooled exhaust manifold ., .. , ..... '
,Drip pan and rnolded vibration mounts •... ,
'!MaXimuIDr-ecommended power take-_of! £1'
front 'pulley at any load . , .. .., ... , ... ,.
Pewer take-oi! limit at rated load .. , .. ; ..
2
High
temperature cut-on ., ... , ......... .
'Total cu. fl .. per min. oLair requi1led ., .. .
Genera.torcooling air (CFM at 180'0 rpm) "
Combustion air.{CFM,at 1800.rpm) . , ..... .
Alr cleaner flame arrester .. , ... , . , .•
Crl1Jk£·rfar .gasolllle fuel ,.
yes
yes
1
yes
Starting by exciter cranking .......... , .. .
yes
yes
yes_ 'yes
Startingl.!y solenoid shift starting mOlar .. .
no
nO
nO
Centr.ifugal Start-Disconnect Swltch .... , ..
not
no •• no
yes
,2
yes
not
2
2
Batter.y charge rate amperes (normal) .. , ..
2
5~0-5
5.0-5· 5-0-5
-Oil Capacity in U ,S.
quarts (refill) , .... , . 2.5
5-0'-5
Charge ammeter scale .,....... . ..... '
5-0-5
3 6
Cooling water flow (gallons per minute) , ..
4
3 6
4
yes
4
4 4
yes yes
yes
yes .yes
,2
hp
2hp
1 hp
2hp
2hp
yes
2hp
lin
120
1'1
120
180'
3f> 35
dry
ele·c·
dry
dry
elec­
tric
elec ­
tric
8
tric
8 8
-l -
,Centrifugalswitch is used with safety cut-aU buLnot for start-disconnect.
.• _ Plus l!2quart for new fil~r .
i . ­
Beginning with SpecF; •• - Prior
to
Spec F.