Idle to high when cold but too low when hot

[Project_Mayhem]

I have a two cycle 1996 Evinrude Yachttwin 9.9. The PO said it had been sitting around a while before I bought it. When I installed it it refused to idle so I turned the idle speed up using the remote throttle/shift control because someone had cut the tiller throttle for whatever reason. Anyways, when I start the engine the idle is super high but by the time I'm ready to come back to the dock the idle is so low that it wants to stall.

Should I look at the idle speed or a/f adjustments first? Also, if anyone can recommend a good resource for carb tuning info I'd greatly appreciate it

 

[kloudie1]

Sounds like idle/low speed mixture is too lean by a little bit.. Caution, because 2 stroke motors don't speak the same language as 4 stroke motors. Take the motor home and put it in a container with water over the cavitation plate so you can run it.. Invite a gear head friend over to listen and advise. Photos and cell phone notes help ya put it back like it was after messing with it.. Problem could be a dirty carb or an air leak at the carb/crankcase gasket. That is where I'd go first..
Dirty carb, I mean.. is the primary suspect..
EDIT: The other thing to check is that the spark advance mechanism is working as it should. Ususally a link from the throttle that pushes on the ignition carrier plate under the flywheel..