A Bright light & a Mirror helps. Loosen the bottom right bolt first. Its the hardest.
The rotary valve cover has four 13mm bolts secureing it to engine, the trick is to
only pull away a little, then slide a butter knife in between the cover and the rotary valve plate and slide the plate against the engine block as you pull the cover away,
thus keeping the rv plate from coming off the splined shaft that keeps engine in time.
The spigot fitting is a brass tube pressed thru the RV cover.