Is there a way to turn solid fuel engines on and off?

@TritonAerospace Thank you

@KJMSpaceStation get the old legacy engine.
It is on my SAF rockets.
Is Gimbled and throttle able

There is a way, but not in the game.

@Zenithspeed now I try it's

you can sort of make a throttleable solid rocket engine, here's how:
1. take out a standard liquid rocket engine
2. set up the size, nozzle, etc. beforehand
3. go into tinker panel (if you have it enabled) and at the bottom there's "edit hidden properties"
4. on the top arrows, click them until you find RocketEngine or something similar
5. find the fuel type, replace the "LOX/RP1" (or LH2 or CH4, depending if you use kerolox, hydrolox, or methalox respectively) with "Solid"
6. click apply, your rocket engine should now use solid fuel
7. if you wish to change a parameter it will revert it back to normal, so you will need to repeat the process once you're done

@MarvinAeroDynamics okay thank you