can i use a 3 channel receiver for my airboat or do i need a 2 channel all most done

what radio do you have and what Rx you are wanting to use?

i have a jr  from my team losi lst and the servos r like new and the receiver is new

I'm still some what in the dark of what you are wanting to do. If you have a matching set Tx and Rx yes a 3 channel will work on the airboats. If you have a 2 channel Tx and a off the waall 3 channel Rx chances are that the Rx will not work with the Tx.

yes it is a maching set

then you are good to go. planning to use the 3rd channel?

maybe a jack plate ? don,t know yet any ideals i like to do mod.s to my boats because i dont have much invested in any of them

maybe a jack plate ? don,t know yet any ideals i like to do mod.s to my boats because i dont have much invested in any of them

jack plate on a airboat? what type of jack plate?

to  help keep back of boat stable when full thottle

You could use it for a trim plate, but a fixed trim plate is easier to set up and cheaper. If you use a servo to move the trim plate up and down with the servo connected directly to the trim plate, you will need a strong servo. If you use a switch/electric motor setup for either a screw drive or a gear assembly you are looking at $ and complexity and more things to fail and give you headaches. Not to mention the possible weight penalty. Dennis

im going to just put a fixed trim tab on it and be done

I don't know where Keystone is but I know Graves Hobby Center(Orlando) carries several different sizes of them that are adjustable. Dennis