First off, signal strength means nothing, its all about signal quality. Double check the elevation on your dish, then check the azimuth with a compass to ensure you are pointed in the right place (or close to it). Make sure to take magnetic deviation into account when checking azimuth. Also, if this is a non motorized install, make sure to set your skew properly.
After getting your adjustments in the right ballpark, then comes the fun part. A signal meter really helps here. I like using a sf-95 signal meter myself, it makes installs a lot easier. If you dont have a signal meter you can use the signal QUALITY meter that on your fortec, along with a tv stategically placed so that you can see it while moving the dish.
Enter a active tp on AMC 4 into the fortec (i would use frequency 11708 V polarity
2170 symbol rate, kuil fox) then watch the signal quality meter on the tv as you slooooooooooooooowly pan the dish to the left and right. I usually move about 1/16th of an inch at a time, then wait 3-5 seconds for the reciever to display changes in the signal.
After you have a signal you will want to "peak" the dish to get the best quality that you can. do this by pressing on the top/bottom/left/right sides of the dish and watch the quality meter (or sf-95 signal meter). If pressure in any direction inproves signal than the dish has to be adjusted accordingly.
After you have done that then move the LNB (while still in the holder) both towards and away from the dish "face" to find the best focal depth, all the time watching for signal increases/ decreases. Most of the time the best signal is with the lnb as far away from the dish face as you can get it, but your mileage may vary
Good Luck