Diesel Shutoff
Had the same problem also two different times with two different repairs. You need to first isolate if the problem exists in the cable or at the the engine. Locate the cable end where its attached to the engine (lever on starboard side of engine) remove the end stop on the cable, then slide out the cable. Try to pull the shut off again, if its still stuck the cable needs replacement or repair. If the cable moves freely, go back to the engine and try and move the lever the cable was attached to, most likely it'll be hard to move. If its the lever thats binding, I freed mine by squirting in lubricant where it enters the engine. If the problem is the cable sticking, you can try freeing it up with various lubricants, I used marvel oil and them lubed it with a cable anti-seeze. If the cable and lever both move freely, I'm not sure what else to do.