Have an old JD400 (serial T5W3D 057511T) , been replacing parts to get it reliable again. A problem it has had since I got it last year is that it will sometimes not shut off right away. Sometimes it takes up to a minute to turn off. I believe from reading it's in the roosa-master fuel pump - the solenoid. Is there a special tool to get to the solenoid? or am I barking up the wrong tree?... and would this problem also cause it not to start up consistently also? It feels like a bad starter (just clicks) then eventually get to where it will crank. I replaced the starter and the key switch so far. Battery is 2 years old. Many thanks all! JoeR