Idles slow and dies when trying to get it in gear sometimes, but it comes out of the hole and runs good anything above idle to WOT, changed fuel filter, plugs and rebuilt the fuel pump, out of ideas for cheap fixes, any suggestions would be appreciated

I'm going through basically the same problem and I thought the same stuff you did it was the (STP) it controls the rpms on the power board if they ever get out of sink it will do that hope this helps

Ditto- My 2001 200 at idles sounds like a real bad azz (almost like a Harley), but often I put it in gear, it makes me look like a real doof and dies. I think she just wants to run.

Might try getting composite reeds to help with the idle. I have Chris Carson reeds on mine.

The reeds are a problem on these motors. Have seen several broke or cracked when trying to fix running and idle problems.

I'm still stuck with tryin' ta figure out what this is and how it can get outta sync????

I'm kinda leanin' towards tha tpi, leaky injector and/or o-ring, idle timin'.....

thanks guys I guess I'll put it in the shop

There is a MAP sensor on the intake that can sometimes cause this problem. Also, if you are running a "hot foot" verify that the idle screw on the back of the throttle has not come loose and backed off - causing low idle problems.
Mercury used steel reed valves in these engines, so you should not have a broken reed - if you did, the engine will cough at a low idle and will not have enough power to plane off.
This problem can be tied back to power pacek,stator, or timing base - but these would be at the end of my list.

Check simple things first!

I believe it is supposed to be TPS - Throttle Positioning Sensor. These things can cause you trouble.

This sensor sends information to the computer to tell it how far the throttle has opened, in return, how long to hold the injector open - more fuel.

"Hot Rodders" back in the day, would advance these some to get more power from the engine.

Mercury would have marked the original position with a yellow paint maker. You can look on the sensor and it should have two adjusting screws. You can realign these with a Mercury EFI Tool -computer.