@dave r said:
Your model needs a lot of help.
Reset the axes first--I don't know why you have them screwed up but you do. Then switch to the standard top view and hit Zoom Extents. Your model will show in the lower right quadrant of the drawing window. This indicates there's some hidden or very tiny entities at some distance from the model. Turn off your section plane and clean up the garbage. There appears to be a great deal of bad geometry. There is ungrouped geometry and poorly drawn stuf. Once you clean it up, Zoom Extents will make the model fit closely to the window and you'll be able to print the way you want.
Thanks David, that must be the problem. I started working on this model quite a longtime ago, with little experience of SketchUp. I indeed did find some tiny entities and cleaned them up. The model now fits better, but there must still be some more that I cannot find anymore. But I am happy to know the reason.
Thanks again!