94 Evenrude 15hp - Hard starting

[mikeschumann]

I have been have lots of problems starting this engine. Out of desperation, I opened up the case. When I moved the red lever in the attached photo to the up position, it created a hissing noise. I put the lever back down and the engine started fine.

1. What exactly does this lever do?
2. What are the potential underlying problems here?

 

[racerone]

That unit is the electric primer valve.-----Pushing the key in while cranking the motor over ??-----The red lever opens the electric primer valve.----Used should you have a dead battery.