Hi guys, got a B2400 with 1100 hrs. After starting and warm up at low speed when I go to WOT to operate the control lever will not stay in position and rpm's will drop a few hundred. I can move it back and engine speed goes up to normal 2450 but will not stay unless manually held there. Weird thing is after awhile and numerous times moving it to WOT it will eventually stay in position. Is there some area where friction holds in place that can be tightened? Doesn't matter if it is hot or cold out, it does it for about the 1st 15 minutes of operation. Any help or suggestions would be greatly appreciated.