General description of JONSEREDS 49SP
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1. Anti-vibration mounts. 2. Rear handle. 3. Throttle safety catch. 4. Throttle catch for starting. 5. Stop switch. 6. Bar
mounting studs. 7. Oil strainer cap with safety chain-guard pin. 8. Clutch guard. 9. Cylinder cover. 10. Front handle.
11. Air filter cover. 12. Choke control. 13. Throttle trigger. 14. Fuel tank cap. 15. Adjusting screws for carburetor. 16.
Lubrication hole for starter spring. 17. Recoil starter. 18. Starter handle. 19. Adjusting screw for oil pump feed. 20. Guard
for right hand. 21. Chain bar. 22. Saw chain. 23. Muffler. 24. Built-in vibration damper. 25. Oil tank cap. 26. Oil pump.
27. Drillings for bucking spike. 28. Chain tension adjusting screw.
Jonsereds 49 SP is powered by a single-cylinder, air-cooled,
two-cycle engine of the loop scavenging type.
The ignition system consists of a flywheel magneto made
by Pagani. The ignition coil is separately located outside
the flywheel.
The fuel tank has a check valve to prevent pressure or
vacuum build-up in the tank.
The carburetor is an all-position Tillotson diaphragm type.
Lubrication of chain and bar is by an automatic pump
with adjustable oil feed.
The starter is made up of a recoil unit with a nylon rope
and rewind spring.
Chain pitch 3j8" or 0.325 inch.
Drive link gauge 0.058 inch (i.e. thickness 1.47 mm).
Chain speed 3540 feet per minute (18 mjsec.) at 8000 rpm
with an eight-tooth sprocket.
Engine displacement 3 cu in (49 cc).
Compression ratio 9: 1.
Bore X stroke =1.732 X 1.260 inch (44 X 32 mm).
Fuel tank capacity 1* US pints (0.8 liter).
Oil tank capacity * US pint (0.3 liter).
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28 27 26
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Engine
maintenance
The engine is tested and preset at the factory.
During its first 10 to 15 hours of operation the engine
should not be run continuously under maximum load. Cut-
ting should, however, always be carried out at full engine
speed.
Clean the cooling fins and air intake screen regularly or
the engine will run hot and be damaged by overheating.
Check the spark plug about every second week. The gap
between the electrodes should be 0.020 inch (0.5 mm). The
spark plug has a relative short service life in a two-cycle
engine. The manufacturers recommend spark plug replace-
ment every 75 hours of operation. Make sure you get
the right spark plug with the correct heat value, i.e. the
same type as that originally installed by the factory.
0.020 inch (0.5 mm)
Spark plug gap
Remove the fan cover and cylinder cover once a week to
. clean the cylinder fins.
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Bar and chain installation
A. Clutch guard.
B. Inner bar plate.
C. Bar mounting studs.
D. Chain tensionpin.
E. Oil hole.
F. Outer bar plate.
The saw is suppliedwith the chain and bar removed.
Follow thesesteps for installation of the chain and bar.
Remove the clutch guard (A) and the outer bar plate '(F).
Check that the oil hole (E) in the bar is clear through to
the chain.
Fit the chain on the bar and over the sprocket. Then put
the bar over its mounting studs (C). Check that cutter
edgesare facing forward on top of bar.
Make sure that the chain tension pin (D) fits into the hole
in the bar. Replace the outer bar plate (F) and the clutch
guard (A). Tighten the two bar nuts finger-tight, just
enough to keep the bar in position.
Hold the bar tip up, and tension the chain by turning the
adjusting screw clockwise. There should be a light tension
in t),.. chain, but it should still move around the bar freely
wh\...lulled by hand.
Tighten the two bar nuts securely with the universal
wrench supplied.
Fuel.mix
The fuel tank capacity is I* US pints (0.8 liter). The
octane rating
of the fuel should be about 85.
Contact your Jonsereds dealer concerning the grade of
oil to be used when preparing the fuel mixture.
Prepare the fuel mixture in a separate gas can, and shake
well before filling the tank. Make sure the can is free
from impurities. Use a funnel with filter when filling the
tank.
Gasoline
B
C
D
E
F
@ @
Never use the saw with a chain that is too slack.
To install aqd tension the chain, always use the universal
wrench.
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4901204
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Chain lubrication
The oil tank capacity is * US pint (0.3 liter). Chain
lubrication is automatic. There is no risk
of the chain
running without oil. Always use special saw chain oil
with good adhesion.
Choose the right grade of oil, i.e. with suitable viscosity
for the time of the year.
Never use oil whichis too thin for the climate.
When filling the oil tank, check for impurities in the oil
which can ruin the oil pump.
The use of waste oil for chain lubrication is absolutely
prohibited!
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