Hello, new to this forum with a question

Had a "tech" out to rebuild the fuel regulator in one of our Toyota forklifts yesterday, and after he did that now the lift won't stay running. The larger solenoid on the regulator works and clicks with or without the TWC fuse installed. the smaller solenoid on the top of the regulator I don't believe is clicking on. With the fuse installed propane gas will flow out of the smaller hose running to above the carburetor with key on but will quickly stop. Without the fuse the propane gas will continue to flow as long as the key is on. Without the fuse installed I can unplug the upper solenoid with no change to engine running. With the fuse installed it will quickly start then die. Any ideas or questions I can answer to give a better image? Thank you.