Losing prime

[spareparts]

if you think about it, the primer bulb will not stay hard if you are running the engine, the fuel pump pulls a vacuum on the line, which overrides the antisiphon valve in the tank, drawing fuel up thu the line. It will draw fuel out of the line/primer bulb till the vacuum overcomes the anti siphon valve or the resistance in the length of line/height of fuel drawn. the only time the bulb is completly hard is when you prime it up to a point of pressue ahead of the bulb against the seats in the carb. Its normal for the primer bulb to not be hard after you run the engine, for that matter, its normal for it to be soft after it sits for a long while, the check valves are not that good in a primer bulb. I do recomend using only an OEM primer bulb, either Merc/ yamaha/ or Bombardier(OMC). I have thrown dozens of fairly new Moeller and Sierra primer bulbs in the trash