So I was looking over the boat to make sure all is good and came across this item after wiping it down noticing that it had a cap to fill fluid. Not sure what this is and what fluid goes in there but it looked low. Can anyone tell me what it is and what fluid goes inside. This sits in the engine compartment on the right side way in the back corner.
Boat specs
2005 1800sr3
Merc 4.3l engine