Thanks Greg, great info !!!
Couple of things, compression appears to have some head work, these are normally about 125 PSI.
If you have the total hours that I would like also, this will give me an idea what state the stator might be in.
Not sure what you are seeing when observing when looking the carbs, but that sound somewhat normal.
So here is what I need you to check initially, something in your original statement, he idled a long way in five mph zone, I need you to check all the exhaust hoses, inspect for ANY leaks water or exhaust, pay close attention to the hose that connects the muffler (attached to the exhaust manifold) to the waterbox, located on the l/h side of ski towards the back, that hose that connects those two parts gets burned from the inside when going slow from the pump not pumping enough water (pressure down) when going through no wake or long 5 mph zones.
Next check the big hose that connects the waterbox to the outside of the hull, these hoses when water deprived will blister on the inside and then will block off exhaust when pressure builds in the exhaust.
Also I have seen where baffles can break loose in the water box and cause obstructions when under power.
By the way, you know you cant have ANY exhaust leaks when the unit is running, so run the ski n a flush and observe for any water or exhaust smoke.
This is a good place to start, if we come up with nothing we'll continue.