Thread: Help! Help starting OS 40
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Old Nov 20, 2012, 03:34 PM
Brutus1967 is offline
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I convince things to work
The Netherlands
Joined Nov 2009
4,622 Posts
Not that difficult.

First make sure, high speed needle is set correct.
Then run the engine at idle for a longer time. Preferrably close the throttle in a brisk way, as the way it takes on idle in the first few seconds tells tales
If it slows down and dies sputtering, it is (much) too rich, open the air bleed a little. If after closing the throttle from full, it takes on idle than slowly revs up and dies, it is (much) too lean.

Fine tuning of the idle mixture is done looking at the way the engine takes up throttle. From a 15 to 30 second idle, open the throttle quickly.
If it hesitates and sputters before running up and gaining speed "slowly", it is (slightly) rich.
If it hesitates only once without sputtering, then either dies or takes on full speed, it is slightly too lean.
Adjust accordingly, until the engine will take on full throttle immediately, after a prolonged idle.

It is important, that you let it idle for at least 30 seconds, to get the engine stabilized on the idle mixture.

When adjusted correctly and with the tank in the correct position, the engine
should also take on throttle reliably when the nose is pointed upwards 45 degrees, although it is acceptable that it will not accelerate as smoothly. As long as it picks up reliably, it is OK.

Brgds, Bert
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