I remeber the ad campaign of "drive it like you hate it" and have followed the philosophy with all my Volvos. You may be experiencing to much draw with the starter hot--does it sound different? labored? A simple amperage draw tester will tell you if it's in the right range. With the warmer weather now, you may have flooding after shut off. The gasoline percolates in the float bowl and winds up washing down the carb throat. Starting it by pushing and clutch dropping gets the motor spinning much faster than the starter motor could ever do. Try the starter with foot to the floor to open the throttle to see if there's a difference-or pull a plug, check for wetness/gas smell. Another possibility--you aren't by chance using the choke (needed only for cold starts) on the warm condition attempts? Unless the car sits for many hours it should not require choke to fire up. A valve adjustment should be done so you know it is correct--but that will not stop oil from being pushed out the breather vent--often a sign of over pressure in the crankcase (maybe worn rings - or clogged up crankcase vent system), check the fitting on the intake manifold and the pcv valve.