Is it ok to use steel clevis everywhere instead of plastic ones??

yes, if you want to use on throttle of a gaser use nyrod to the extrnsion to the servo

You can use steel everywhere except on the carburetor. This is usually a steel arm and the vibration against the steel clevis may cause radio interference.

Dr.1

Depends - if you are dealing with a gasser you have to be sensitive to possible interference issues with respect to the ignition. You don't want any continuous metal paths running from the area of the ignition to the Rx area. Also, in any plane, you typically want to avoid metal to contact anywhere in the plane that could vibrate and generate RF emissions - which could cause interference.

I'm building a Top Flight Gold Cessna 182. 120 4 stroke. So if I use steel except for the motor I should be ok??

Thanks for your answers

metal on a glow motor is fine even on a gasser as long as you don't use a 2-25 or 4-40 metal from from the clevis to the servo. thats were nyrod comes in handy.

I use nylon clevices throughout my pattern ships , for the sole reason that they wear less than the steel ones. Steel pinned clevices will wear out the nylon control horns faster, due to all the contaminates they pick up when taxying, so my recommendation is to use nylon throughout the aircraft , you wont regret it .
the_madgenius

AVFLIER, if your engine has a nylon throttle arm (not metal), you can use a metal clevis there too, you just want to avoid a metal-to-metal connection.