Side valve heads are dry so a blown gasket leaks out fuel not oil
The only things that will leak oil from the top will be the top oil seal & the valve chest
I’ve seen L-Head engines that will blow oil out a head gasket, because they are either stored sat an angle in a position where oil will leak into the cylinder, especially when they are over filled or gas diluted.
Certainly looks like blowen head gasket , check head bolt torque as a clue , if 1 or more are loose when they should be 140 -150 in/lb , if it was a top flywheel seal you would see oil and dirt sticking to top side and down over r/h side of c/case .
, and as per last reply it's more likely that it fuel rather than oil comming out unless it's been stored on a angle and then run , or even been wetsumped or over filled
Could that be a mixture of fuel and oil blowing out the front of the sump gasket and bouncing off of the cooling fins out the right side? I'm more asking rather than telling. I think this is the type of setup where if the carb leaks the fuel only has one way to go, into the crankcase because the airbox will block the choke side of the carb. I've had to do a couple of sump gaskets on mowers that the crank was overfilled with either oil or gas/oil mix.
