every time I drop my boat in gear my engine dies. Idle is at 1000rpms put it in gear and it drops to 300rpms and I have to catch it my moving throttle quick. I have changed power valves and had the carb pro-cleaned...same results... any ideas???

Pull the idle mixture screws out about an 1/8th turn each. Should fix it...

If not, the idle circuit might be blocked.

Idle is lean. Back out idle screws evenly like mentioned above

Idle is too high too, which will make the mixture screws less sensitive.

Bad plug(s), plug wire(s), cap/rotor, plug wire on wrong cylinder, incorrect timing, low compression, and etc can cause you to turn the idle speed up and still have stalling condition when put into gear.

first question would be why does it idle at 1000? what is the engine? unless it is a very stout engine there is no reason to idle that high.

you may be uncovering the transition slots which cause the idle mixture screws to be ineffective.

You have original flywheels. Didn't recently switch to aluminum etc? Also watch your carb linkage as you have a friend drop in gear. Or shift manually with cable off and do it yourself and see if there is any changes. You can also maybe bump the primary jets up a couple sizes and see if it improves or gets worse.

Like SB said be sure and ck plug wires/firing order etc. Seems to be a lot of that going on lately. You have chokes or no? Look everything over carefully. Did the problem begin before your carb guy went through carbs. Just make sure no gaskets are on upside down etc. also is this the only problem? Everything else cool in the gang running wise?

Maybe out of the question however cables stretch over time and adjustments need to be made so make sure your not out of whack there including neutral safety and so on.

primary jet should have no effect on idle circuit.

ok, I will try that this Saturday