as i recall that fitting was to vent and drain old oil and combusted acids from the crank case - common in 4 strokes.....put a piece of tubing on it long enough to stick out from under the cowl. After a days flying, you can use that tubing to put after run oil into the crank case to prevent corrosion...run the engine dry, then squirt aro into the tubing

Now that's as I recall. Others may well have other opinions and suggestions - feel free to jump in..

Thank you , I seem to have an issue tho , will not start , seem to be low on compression ,

I checked the plug , made sure the pitson is moving ....  ,, 

I need some pointers on this to debug,   2 strokes I am good at  fixing

should I pull the valve caps make sure   vavles are opening ect ....

Yip, that's what it was ,   stuck intake ,   now I seem to be missing one lock nut on the tappet,  anyone know what size  nut this would be ,  I have checked the exploded view and it does not say

had a good friend and flyer visit last evening and adjust the  clearances for me , we now have good compression ......