Starter not disengaging

I have a LS160 when I start it the starter will not disengage the fly wheel after the engine has started. I can turn off the ignition switch but the only way it will shut down or disengage is when I disconnect the battery. I have replaced the starter and ignition switch. Any suggestions?

Did you put the shims back in if any

On the left side in the engine compartment, right above the fuel tank and up against the firewall you will find the engine compartment fuse and relay block. You will see a cover with a wing nut to loosen to remove the cover. Do not remove the cover. Right below this cover you will see two plastic covers pointing to the back of the machine. Remove the cover on the one closest to the tire. The start relay is under this cover. Replace the relay.