What is the vent cap on the top of Oil Reservoir Tank for?

[Stephen L.]

Could anyone kindly tell me why there is a vent cap on the oil reservoir tank of my 1993 Mariner 75 hp 3Cyl? It is an oil injected motor, and the tank is full. Should I leave the vent cap open while running the motor? I just purchased and had the motor installed, and want to make sure that I do everything right! I want this motor to LAST!!! Thanks...Stephen

 

[Dunaruna]

Re: What is the vent cap on the top of Oil Reservoir Tank for?

Open for running, closed for trailering (so oil does not leak out when the motor is fully tilted).

 

[Stephen L.]

Re: What is the vent cap on the top of Oil Reservoir Tank for?

Dunaruna thanks for the quick reply, and for answering my question!