my 31hp longtail (stock) idles very low, if i crank it it will run for a few secs then get lower and lower and lower rpms then kill. i want to adjust my idle up alittle so it wont kill can anyone post a pic of the idle screw or maby give me some good instruction? thanks !

First be sure fuel bulb is still firm and motor is not starving for fuel, and that air cleaner is not full of crud, if it is dying with trottle up some your idle screw ain't gonna help.

Second see if motor position matters, mine will not run if I let the tiller
handle up when cold, runs great in tilted position, after 30 seconds or
so it stabilizes and then doesn't care anymore.

Third there is no substitute for good new 93 octane fuel, boat tanks are bad about condensation of water in the fuel, clean or replace your fuel filter/seperator.

If those are covered and you still have trouble it may be time to strip and dip that carb in some cleaner and do a retune. There are good books available if you need them.

If it's a briggs, look just below the choke on the front panel. There should be a small hole. With a skinny screwdriver you can adjust the idle.