Factory needle settings, OS and TT

[Farmer Giles]

I know this should be in engines but I want to carry on playing while there is still some light....


Hi, I'm just rebuilding an OS37SZ and I don't know what the factory needle settings are.

Also when setting the idle jet is the fully wound in position with the throttle closed or fully open ??? If I wind in the needle to the stop with the throttle closed and then fully open the throttle I can wind in the needle a couple more turns so I don't know where to start from counting my turns out.

I checked my TT39 and it's the same so I don't know where to start from on that one either to get my base settings.

Just want to get good base line settings on both engines so I can start from the beginning.

So in short I need standard needle positions for the OS37 and TT39 and also where to start turning from for the idle needle.

thanks

[Birdie4x4]

Sorry cant give you base settings but would say idle mixture will be set with throttle closed as this is where it will be when running.

[sacko]

http://manuals.hobbico.com/osm/37sz-h-manual.pdf

Its usually somewhere in there

[Farmer Giles]

Thanks Paul, I never think about googling for a manual...

If anyone else reads this the standard settings are :

screw out the mixture screw until it's flush with the housing then screw in 1 whole turn. The screw should sit 0.5mm below the housing. For the main needle standard is 1.5 turns out but I will be starting with 2 as I am running in a new piston ring.

cheers

[Dedcalm]

I always just get the manual from O.S. Engines Home Page