Small Engines (Lawn Mowers, etc.): compression etc, bubble gum, compression release

Question
General questions that shouldn't require model#s--I have a briggs 3 hp with compression psi of 35 that is extremely hard to start and wonder if that is the problem--what is the usual psi?  Also have a Stihl trimmer with a new ignition that will only run for at most 2 seconds and punching the primer which is full of gas  does not permit it to keep running as it normally would if a carb problem--  thanks

Answer
Question#1  35psi should be enough to start the engine as that is the compression reading during startup which is not actual due to the compression release on the camshaft.  I generally see ranges in the 15 to 40psi range.

Your Stihl trimmer sounds like it has carb problems.  Spray a lil carb cleaner or WD40 into the carb and then try to start it.  Does it start and run for a few seconds then quit?  If so you need to either repair or replace the carb.  Also check your fuel lines and filter to make sure it hasnt collapsed or turned like a bubble gum consistency.