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CONDENSER
Figure 2. Magneto Assembly
1.
4 CARE OF JACOBSEN ENGINE
GENERAL -
An
engine received for service will
reveal characteristics or faults of operation that
will aid in proper servicing. For instance, oper-
ating an engine with too rich a fuel mixture or use
of a poor grade of lubricating oil will hasten carbon
formation on spark
plug,
cylinder exhaust and in-
take port holes, piston, cylinder head and muffler.
Carbon formation at any of these points will reduce
engine power considerably. Build-up of carbon de-
posits can prevent an engine from running. When-
ever reinstalling cylinder head or muffler, use new
gaskets and tighten securely.
If
cylinder head is
not tightened securely, compression leaks will re-
sult.
Recognition of operation characteristics is a time
saver when performing minor or major overhaul.
SPARK PLUG - Normally a spark will jump the
gap between electrodes approximately 3000 times
a minute. It is important that a plug be kept clean
and the electrodes gapped to O. 035 ". Clean and
reset gap during every overhaul. Deposits on the
electrodes are sometimes caused by lead in gaso-
line or additives in oil. Proper adjustment of c ar-
buretor, correct types of gasoline and oil and the
recommended fuel mixture will prevent excessive
deposits and keep fouling of the
plug
at a minimum.
Always be sure seat on cylinder head is clean and
that the copper gasket is used with the spark plug.
NOTE: Always use a "J
"
type spark plug to min-
imize bridging of the electrodes by foreign depos-
its.
ENGINE SERVICE MANUAL
AIR CLEANER - Three types of air cleaners are
used on Jacobsen engines: an aluminum foil type
cleaner, a paper filter or an oil bath type cleaner.
All are subject to clogging and restricting the flow
of air to the carburetor.
An
inadequate supply of
air will prevent engine from producing maximum
power and also cause the excessive fuel in the
mixture to burn improperly. Carbon will build up
at a fast rate in the cylinder and add to inefficient
operation of the engine. To properly clean the air
cleaner remove from engine and disassemble.
FOIL TYPE CLEANER. Wash and rinse thoroughly
in gasoline or other solvent. Shake off gasoline or
solvent and immerse in clean SAE 30 oil.
Allow
excess oil to drain off before installing.
PAPER FILTER. Brush or wipe outside of cleaner.
Tap gently to loosen dirt from inside of filter.
Do not oil or wash filter. Filter can also be clean-
ed by gently blowing compressed air from the in-
side.
If,
after extended use, filter is too dirty
to clean properly, replace with a new filter.
OIL BATH TYPE CLEANER. Remove cover from
oil reservoir and dump out old oil. Wash cleaner
in gasoline or other solvent. Dry cleaner thor-
oughly
.
Refill to level indicated by arrow with
same grade of oil used for engine lubrication .
.
EXHAUST PORTS AND MUFFLER
To clean carbon remove muffler and scrape and
clean all carbon from inside
muffler.
Use a
screwdriver or similar tool to clean out carbon
from exhaust ports. Make sure piston is at bottom
dead center when scraping ports.
When further disassembly is required to clean out
carbon from engine
,
remove cylinder head. Scrape
carbon from cylinder
head,
clean off top of piston
and also clean carbon deposits from intake ports.
To reach ports rotate crankshaft until piston reaches
bottom dead center.
1. 5 FUELS AND LUBRICANTS
Proper mixture of good REGULAR GASOLINE,
GRADE - 70 to 85 octane
,
and non-detergent oil
is necessary to obtain top performance and trouble-
free operation of two-cycle engines.
Do
not use
low octane gasoline or cleaning fluid.
This will
cause engine
over-heating,
pre-ignition, sticking
rings, excessive carbon in exhaust ports
,
and foul.:.
ing of the spark plug.
The oil mixed with gasoline lubricates all moving
parts of the engine as the fuel-air mixture is drawn
into the crankcase and cylinder. Always mix a half
pint of Jacobsen oil or a high quality outboard
motor oil to each gallon of regular grade gasoline
in a separate clean container.
Never use dirty
gasoline or oil.
Use SAE 30 oil
,
if
it is necessary to use other
than Jacobsen or outboard motor oil.
7
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