Carbs spitting fuel

[MAL]

I have a 97 SeaDoo Explorer with a 717 engine. It starts fine and runs ok until it gets warmed up. After about 1/4 mile of riding it will start to bog down and will not maintain plain on the water. I can tickle the throttle and and get it to take off again, but it will continue to bog down every time. I took it for a ride with out the seat and air box so could watch it. When it's bogging down it spits fuel mostly from the Mag carb. What can cause a carb to spit fuel?

 

[MAL]

Is there a valid way to check the crank case for air leaks on an installed engine? I have started to block off the intake and exhaust...I used rubber roofing in the place of the gaskets. I connected the gauge and pump to the pulse fitting. My gauge was not accurate enough at low pressures so I will try again with a better gauge tomorrow. I am not sure what the pressure was, but I did see air bubbling up in the oil return line.

Do I need to pinch off the oil lines?
Is there a pressure spec on the crank seals?
Is my test even a valid test?

 

[MAL]

Update

I have checked a couple of things that may be clues. I swapped the needle, seats and springs in the carbs to see if I could move the spitting to the PTO carb. It was still spitting from the Mag carb when it bogged down, but if I choked the PTO carb with my hand for a second or so it would take off and run fine.

Also in my process I discovered that the the rotary valve cover has some scratches, one scratch is just big enough to catch my fingernail on and there is a gouge from a small screw or bolt. I am not sure how significant this is.

So It looks to be a fuel delivery problem, but I am not sure if it is one or both carbs...or if it could be the rotary valve cover.