It is NOT a valve issue.------Load test the battery.-----Take starter apart for inspection.-----Drain / change gear oil.-----Install new water pump impeller before your first expedition.
Good compression would show about 130 on my gauge.----So you have a bad guage or a motor that needs work.----Pull bypass covers on the 100 PSI cylinders.----Look at pistons / rings.
There is usually a bit of air above the oil.-----It gets blended in with the oil.------The tiny bubbles that make the oil look " milky "------Let that oil sit for a week or so and see what happens.
I have rebuilt numerous crossflow V-4 and V-6 outboards.----I know they suffer from the broken ring syndrome.----It is easy to understand why the upper ring breaks !!
Draw a picture of the top piston ring.-----Now consider what happens to side clearance when.----piston wears.----when ring wears.----when cylinder wears !!!
Have never seen a warning in an owners manual / service manual or label on a portable tank about running out of fuel.----Agreed that common sense has gone and left us..----Folks just rely on their phone to survive I think.