JD 770 low RPMs on start up.

[TommyAndrews]

Our high school uses a JD 770 and here today it has had problems on start up. When cold started the rpm is very slow to climb it took 10 minutes at WOT to get to 1000 rpm. It slowly seems to clear up as it runs. The fuel filter is new and has plenty of fuel at it have not checked at the lines yet though. Was told at first start up this morning it smoked what they said was white smoke for a bit as well any ideas?

 

[TommyAndrews]

Just checked and was able to verify smoking on start up but its blue not white.