Gene, OK, your talking two different controls
Yanmar 3GMs have the cable at the control panel hooked to the fuel cutoff on the fuel pump. The decompression levers are usually not hooked to anything but can be if so desired. I think it's a control thing with some operators.For me, I eliminated the cable and went to a solenoid shut off. I also installed a push button switch to crank the engine, at the engine box side. A matching switch also activates the cut-off solenoid. It's mounted next to the start button and even uses the same power feed. Now I can kill the engine or start it at the cockpit panel or working on the engine below. See photos #46 & 118 on my web site. And this is a very worth while modification. I've never heard of an unhappy customer. Oh, the solenoid is in #47