I have a Delta 10" contractors table saw series 2000, when I set the blade to 45 degrees to rip, the blade hits the inside of the table insert.

Question edited for typo.

Here is the manual. I am guessing anticlockwise like all fixed screwed objects. Page 6 I think?

http://vintagemachinery.org/pubs/1191/17422.pdf

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The most important thing is that the blade and riving knife are centered with each other. If not, you may have to shim the riving knife.

The bolts that hold the carriage under the table are intentionally sloppy so that you can loosen them and align the blade/knife with the miter gauge slots.
Lay a long metal straight edge against the side of a carbide blade teeth with the blade all the way up, and make sure the straight edge is parallel with the miter gauge slots in the table. Then tighten the bolts on the underside.

The owner of Inline Industries (he invented the PALS product that lets you get a precision alignment on a contractor saw) has a video that shows how to add grease fittings that will make blade raising, lowering and tilting very easy. Check him out. He sent me the video when I bought the PALS.

Left-tilt, right-tilt refers to the direction the top of the blade can be tilted when it is not straight up and down. There will be an indicator on the front of the saw, normally pointing to zero. When you adjust the blade away from zero, if it tilts to the left, it is a left-tilt saw.

Your question is not very clear. Here are several answers.
By tilt you may be speaking of bevel adjustment 0 - 45 Some saws have hidden under the table or obvious positive bevel stops or screws in the table top for 90 and 45 degree. Adjust them.
You may have a bent or warped blade causing the "tilt."
Thin blades may be stiffened with blade stabilizing washers $14
With the saw unplugged remove the blade. Grab the threaded arbor shaft and pull it up and down. Next push the shaft straight in and out. If there is wiggle the bearings are worn and may need replacing.

I ran into that kind of problem with my Craftsman 10 table saw. I (an usual) over analyzed the problem and looked at moving the entire motor assembly from left to right slightly. In the end, I found that that the blade stablizer plates I used on the left and right of the blade, moved the blade that little bit needed to make the blade tips make contact. I removed the two stablizer plates, reinstalled the blade with the normal to flat washers and gave it a try. The blade now cleared the insert when pushed all the way to 45 degrees.

You might want to look to make sure there are no extra washers/spacers on the arbor that might move the blade slightly left or right from its normal position.

Narrow throat plate should work. Sure you have the blade installed correctly with arbor washers?

Here's something to try. Get a dial indicator or a drop indicator to measure the blade wobble. Clamp the indicator to your miter gage or use a magnetic base or whatever. Position the indicator so that it contacts the side of the blade as near the outside diameter as possible, then rotate the blade by hand. If there is any warp to the blade, or bend in the arbor, or something out of square where the blade mounts on the arbor, this will pick it up. If that is all good, maybe you have a couple of teeth that were miss-sharpened and are sticking out to the side more than they should (causing a virtual wobble at the tooth end). You could position the indicator on the side of a tooth, then slowly rotate the blade backwards looking for the max reading on each tooth. You should repeat this on the other side of the blade too. Total wobble should only be a few thousandths. Good luck!

use a square to sure up your blade so you are at a true 90 degree

The Blade Arbor is held to the bottom of the table with mounting screws and stop/adjusting screws. Loosen the mounting screw and adjust the stop screws to make Blade true with miter slot.