It's nice to be back. I needed some time away after closing my shop, to get my head on straight.
OK.....
So... once restarted, "Feathered" and cleared out.... It's 100% fine until you shut it down again????
I can shut it down, and restart within a few minutes and it acts fine. No bog, no starving for fuel..Nothing..Perfect
If yes....
The it's easy.
1) There are too many fumes in the bilge.
TEST: Try pulling the seat off for a minute or two, and use a fan of some kind to blow in fresh air before taking it for a run.
Never thought of that, will try to pull the seat next time
Solution: Mount a bilge fan, and/or find the source of the fumes. (most likely the aftermarket air filters. I bet they are wet with fuel after a run)
2) The high speed check valve is leaking.
Test: unfortunately... there really isn't one. But, it will show it's head again after a long idle.
If riding normally I can idle for a good 300yds and gun it and take off normally
Solution: Take the carbs apart, and check them.
3) You don't really want to hear this one.... But Proks don't like 720/800 Seadoo's. every time I hear about tuning issues... that's the filter in place.
Test: Put the stock box back on.
Dont really want to , but might have to try!
Solution: live with the small warm-up/re-start issue if it's running ok elsewhere.
Basically... on that re-start... you are simply running out of fuel (or out of fresh air) when you open the throttle. (in transition) SO... if there isn't a mechanical issue (like the high speed check valve) Then I would go up one more size on the pilot jet, and then close the low needle about 1/8th of a turn, to trim the fuel back at idle.
Not sure of the jet sizes that came with the kit.
I was thinking i may be flooding it at idle with the lows since i never checked them.
Thing turning them back 1/8 turn could help?
One last question to you.... since things are mod'ed... do you have accelerator pumps on your carbs? (a 96 XP normally shouldn't)