This Ross engine has a geared reduction drive and a dry clutch. The clutch means that the propeller is not spinning when the engine is on idle. As the engine spins faster, two shoes open out and then it engages the housing inside and hence drives the propeller. It should not have any oil residue there though because it is a dry clutch. It doesn't need any lubrication but it's got some seepage here somewhere so we're going to take the reduction drive off and have a look inside and see where this oil is coming from. Just make sure when you're taking the last bolt the reduction drive doesn't fall off. This needs a little tap or a bigger tap. Voila! Here is the clutch, the dry clutch. Okay we can see these are the two shoes that open out, sit with centrifugal force. Okay as the motor spins faster these open up more and they grab on the inside of the bell housing causing this to spin and hence the propeller as well. And you can see I'm twisting this clockwise and this is going the opposite direction. Okay this is a geared reduction drive. It spins the propeller in the opposite direction to the rotation of the engine. But there's a seal behind here and the seals probably gone a little bit bad and we can see that there's some oil residue around here so we're going to need to replace the seal. Great cleaner, not WD40.