13. Normal operation, maintenance, and additional information
(1) Even for regular use, when you start the engine please run with rich condition for 30-60sec to warm up the engine. And when you
stop, take a minute of idling to cool the engine. At the last flight of the day, make sure to stop by fuel-cutoff in order to make no fuel
remain in the carb.
(2) When you store the engine, make sure to remove all fuel from the tank.
(3) Please charge the battery of the ignition system and RC device enough. (Since an ignition system generates high voltage, be careful
(4) For discharge of the waste oil (breather), connect a heat-proof and gasoline-proof tube to the breather nipple to eject the waste oil, or
diffuse it together with exhaust.
(5) Lubrication for piston, connecting rod, bearing or cam gear is a blow-by lubrication in which the oil in the fuel goes into the crank-
case from the clearance between the cylinder and the piston. Therefore the engine life is affected by the property of the fuel oil.
Please use reliable oil.
(6) Since over closing the main needle causes overheating, adjust a little more rich than peak.
Over closing leads to knocking or engine failure and has an adverse effect on the connecting rod and the cam gear. The case where
the airplane achieves peak completely at the time of ascent is a proper peak of the engine during flight.
(7) After completing ground break-in or operating the engine for one hour, adjust tappet gaps (valve clearances) by following procedure
to compensate initial wearing, while the engine is cold (Fig.10).
(a) Remove the plug and rocker arm covers of the cylinder.
(b) Turn the prop slowly forward by hand, to stop the rocker arm. Further turn the
prop, to bring the piston to the TDC (Top Dead Center) of compression stroke.
(c) Use the attached wrench and hexagonal wrench to adjust the gaps indefinitely
close to zero within the range compression exists. If the gap is lower than 0,
the valve has to be opened at all phases so the compression doesn't occur.
After adjustment, please put on the spark plug and turn the prop forward to
check if the compression is enough.
(d) On checking the gap, securely tighten (but not excessively) the lock nut.
* In the case of the engines for vehicle, small gap is given to tappets to absorb valve
elongation. In the case of SAITO engines, gap becomes larger during operations due to thermal expansion of the cylinder (made of
aluminum). Therefore set the gap indefinitely close to zero while the engine is cold.
Note: Occasionally check tappet gap by those procedure. When the attached gauge (limit gauge, t=0.1mm) comes to be inserted, gap has
been enlarged beyond the allowable limit. Make an adjustment to lessen the gap. Tappet gap is one of the most important factors in the
maintenance of 4-stroke engines. Operating the engine with the tappet gap enlarged excessively will cause poor performance or troubles.
(8) When connecting the exhaust pipe to the cylinder or attaching the prop nut, apply thin coat of silicon rubber (not excessively) on the
thread before tightening. This prevents leakage or loosening.
(9) Occasionally tighten the prop nut and exhaust nut (while it is hot).
(10) When stopping the engine after the day's final flight, please be sure to stop it with fuel cut and see that the fuel does not remain in
the carburetor. Moreover after the flight is completed, extract the fuel from the tank without fail and store it.
(11) See to it that the storage of the battery and the fuel cause no accident.
(12) If the engine is not operate for a long period of time, remove plugs, rear cover, rocker arm covers and wash them with alcohol
enough. Then, after lubricating them, assemble them in the original condition with a plastic bag on.
(13) Please notice that our guarantee will not cover any breakage or trouble on the engine caused
by your disassembling or modification. If disassembling becomes necessary, ask repair for
the shop from which you bought the engine.
(14) Notes for purchasing parts: Please give orders to the shop from which you bought the engine
with engine name, part name or number, and marking (alphabet on the lower face of rear
(15) Take an extreme care for safety when operating the engine or flying the model airplane not to
(16) Muffler maintenance; Because all of our gasoline engines use oil-fuel mixture, there tend to be
carbon buildup inside the muffler as shown in the picture. It will cause some problems on the
exhaust outlet and consequently reduce the power. Therefore cleaning/removing carbon every
about 50 flights is recommended. Using a parts cleaner spray is effective way to remove the carbon inside. Actually, it depends on
the quality of the oil so when you feel the power loss, please check inside the muffler.
(17) An engine for a model airplane is not a toy. Handle it with an extreme care.
All specifications and models are subject to change without notice.
SAITO SEISAKUSHO, CO., LTD.
22-7, 3-chome, Tokagi, Ichikawa-shi, Chiba prefecture 272-0024, Japan
Close to "0" with no limit
Must not be inserted