First things first. You are not turning the nose or edge into the rotation, right? Too many people just haven't thought through the basics of edge and wood, and remember that turning is carving set to power. All the rules about side slip that we use in knives and carving tools apply. You whittle uphill or up grain at peril. Same applies for carving, even when you establish a stop cut. Don't do it on the lathe.
Idea is to let the wood slice itself down the edge of the tool as presented. Means controlling the shear and the skew of the tool so you don't get too broad in the first, or allow the wood to come over the back of the edge with the second. Then you want to cut down hill and, with luck, down grain. Those two pesky spots mentioned are where the trouble starts. More obvious with walnut because the light scattered by torn fiber contrasts so starkly against the darker background.
My solution is to revert to the old ways before the cylindrical "bowl" gouge was foisted upon us. The old boys used forged tools with consistent thickness and bevel angle whether narrow in sweep or broad, hook tool or gouge pattern. If the slope is slight, the tool can shear broadly, but where it steepens, the shear is best reduced, though the skew may be broadened for consistent depth of cut reference.
Take your knife to a piece of whittling stock and see what effects shear and skew produce. Or carve with a fairly broad sweep across the grain. It'll be the same on the lathe, only the work will move, and the tool remain stationary. As a final demonstration, increase the pitch angle (for standard wood vs. edge terminology see
http://homepages.sover.net/~nichael/nlc-wood/chapters/caop.html Fig A-1:2) and watch how the resistance increases at the same shear and skew. That's why scraping takes a steady, light hand. Also why we'd rather cut where we can.
You've received advice about getting a bowl gouge. To compensate for the uneven depth of metal which comes with the cylindrical design, people recommend grinding back the ears and cutting with them. Take a look at this photo and consider which of the tools is more controllable.
http://i35.photobucket.com/albums/d160/GoodOnesGone/Gouge-Curves.jpg
Or encounters no interference from the rest, banjo or even the work itself as you attempt to get the skew angle that allows you to shave rather than lift. Worth acquiring one for final surfacing. They don't plunge well at all because of the broad sweep, so use that "bowl" gouge or your ancient long and strong/narrow hook for that work.
