Hi. The decopressor is actuated from a cam on the hick start spindle.....so it will operate every time the kick start is depressed. The kick start needs to be allowed to come back completelt to the top for the decompressor to reset. if you push the decompressor lever on the engine backwards against its spring (the way the cable would pull it) there should be approx 1/8" travel before it comes up against the valve, you'll notice this, because to push it any further (i.e. open the valve, is pretty hard) i will check that tolerance in my manual.
I usually find compression, after maybe 2-3 strokes of the lever (remembering to let the lever come right back up) about half way through the stroke, then let the lever all the way up and then, NOT TOO VIGOURESLY, boot it all the way.....if the engine is cold, (and on standard carbs) then use full choke, and NO throttle.....my srx on standard carbs seems th work best that way.....but will run maybe for a couple of power strokes then stop, maybe twice, then get going ok....it's always done this.......every one seems to have it's little quirks....thats what we like about them. But do check your plug....and the wiring round the coil area for cleanliness...