how do you set up an engine

[qahwaji123]

Hi i have a zoom 450ic with the stock sx 12 engine i have set it up as the manual says, Which is the high speed needle set 2 turns anti clock wise and the fast speed needle flush with the carburettor. The engine seems to start ok and is fine from bottom to mid stick, But from mid to top stick the engine speed does not increase, Infact it starts to slow down and splutter. What could be the problem. Thanks. The pitch and throttle curves are set correctly.

[del19_82]

I had this problem on my os32sxh & it was because it was running a wee bit too rich. Maybe thats what it could be?

[qahwaji123]

hi if i turn the high speed needle in it over heats and cuts out. and if i unscrew the high speed needle it splutters even more. ??? I just cant get my head around this one. Any help would be great thanks

[steelie600]

weaken low end a tad at a time it will come good soon, remember that the engine will always be screaming its knackers off so the low end is not that important if its too weak. but it will help to lean out top end

[qahwaji123]

Right i have done the pinch test with the engine on idle, as it says in the manual. When I pinch the fuel tube the engine speeds up for about 5 seconds then stops. I have screwed in the low speed needle as it says in the manual and now the engine speeds up for 7-8 seconds before it stops. Im very puzzeled as of what to do ??

[qahwaji123]

In the manual it says to open the fast speed needle 2 turns anticlockwise but the engine splutters so I closed the needle fully and opened it one and a quater turns anticlockwise the engine is fine then cuts out.