Sachs SA 340 - Test-Running and Running-In the Engine; Engine Test-Running and Adjustment; Engine Running-In Period

TEST-RUNNING AND RUNNING-IN
THE ENGINE
Test-running
Start th e en gi ne and let it warm up (ope n the choke as soon as th e engine starts up ).
Final adjustment
Adjust the desired id ling speed of the engine by means of the idling adjustment screw.
Then
slowly vary the se ttin g of the adjusti ng screw of the idli ng j et so that the eng ine
speed
inc reases smoothly when the th r ottle is opened. The main jet is correct ly ad-
justed w hen the eng ine gives satisfacto ry two-s tr oke operatio n und er load and only
slight fumes are disc har ged from th e exhaust. If th ere es excess iv e exhaust smoke
under l oad, turn main j et adj ust ing screw cl ockwise (c lo sing) until smok ing stops and
engine runs satis fact o rily .
If the id lin g speed fluctuat es t oo much or is too high , turn th e idling jet adjus t ing
screw anti-clockwis e (to open the jet) until the e ngine runs s moothly at lo wer speed
witho ut beginning to discharge more smoke from the exhau st.
Running-in period
Even the finely machined surfaces of pistons and cylinders are not so s moot h as the
surfaces
of parts which hav e been sliding again st one another for some time. For this
reason
ever y pi ston requires to be run in duri ng the init ia l per i od of operation. This
does
not call for any speci al precautions, ho wev er, b ut simply mea ns that the eng ine
should
not be r equired to give its ma x imum output during the first 20 ... 30 run ning
hours.
No special gasoline / oil mixture is required during the running-in period, and conse-
quently there is no need to add any special oi ls.
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