VNAV speed?

hi..

can anyone explain how to set up the speed for VNAV...
it is always stuck at 139 or 159 knots or what it is...
how to change? i have tried all spd where i can write something...
like in clmb i set 250 knots but it still fly in 159 knots

regards;Tommy

Hi,
try to activate VNAV not until you have a clean configuration after takeoff. This means Gear and flaps retracted. Then VNAV activates correctly.

Best regards
Roland