1969 Evinrude 18hp tiller

I've got this 69 fastwin that I've had about six years. I only used it once and I don't remember if it worked ok or not...Anyway now after changing the plugs and getting new gas for it ,it fired up on only the second try.. The motor runs smooth but a little high rpm for idle [ I think ].Anyway the problem is that the handle that controls the gas won't twist. Its stuck between start and shift and is not about to budge. I tried kicking it into gear thinking that might help but no change.At the time I had 3 tiller motors and I'am not sure which one i used six yrs. ago...
Anyway now I'm stuck on the bank because my Champion is in for repairs and my spare jon boat is straddled with with a faulty Evinrude... Any one have any suggestions as to what I might try..
Thanks for your time
Ken

Hey... I have a 68' Evinrude 18 HP. Where does it seem to be stuck? Is it the twist grip throttle itself or is it more the motor? I know mine has the ability to set up remote steering and where the tiller handle meets the motor there is a little lever where you can pull to give it gas so to speak. If that is free to move then its your twist grip throttle.

+1
If the lever on the side he's talking about won't move either, pull the cowling off and see if the plate under the flywheel will twist. If nothing moves, try hitting the pivot points with white lithium - someone correct me if I'm wrong, I know that's what is normally used to lubricated throttle linkage, so I assume it would work for this

Just an up date on my tiller problem.I found the lever that needed to move to rev the motor but it had been broken off .While I continued to mess with it I decided to remove the grip.The grip was spring loaded and when it flew off it scared the sh)( outta my dog....but the problem was found. This throttle was packed full of heavy grease and was set up almost solid. That throttle hasn't twisted in years. A heat gun and new lithium grease fixed
my problem. Everthing works find now....without knowing about the lever I would still be twisting that darn thing
Ken