Vent hole on distributor cap? 1987 MerCruiser 230 GM 305

[clattin]

I replaced the distributor cap on my motor this week and saw that the old one and the new one have a vent hole in the side with a fitting that goes on the outside of the housing to which a tube could be connected. Nothing was connected to it on the old one and I've never seen a distributor cap with a vent hole. What purpose does it serve and should it have a tube connected to it?

Thanks!
Chris

 

[Bondo]

Ayuh,..... No tube, nothin' hooked to it,.....

Bein' a metal elbow, it's a spark proof vent,.....

 

[hot rod 18]

-the cap for a boat should not have holes it should only vent thouh the flame arister

 

[Bondo]

-the cap for a boat should not have holes it should only vent thouh the flame arister

Huh,..??..??..??

 

[hot rod 18]

Sorry ibshould havecread post better with my mallery xap ther are two difrent ones one with hole for rasing and the boat with holes. On the merk the fitting is just a flame arester nothing hooks to it