I have a Dixon Ram 50 ZTR mower that is around a 2003-2005 model year. (Don't remember exactly). It has a 22 HP Briggs twin cylinder "ELS" engine. I noticed earlier this year that when I would turn the key off the engine would not shut down right away. It was not dieseling it would just take 2-3 seconds for the engine to die. I thought maybe the ignition switch was going bad so I let it be. Earlier this week I started the mower and I could tell it just didn't sound right. It had plenty of RMS but the sound from the exhaust sounded a little "deeper" to me. Almost like the choke was not all the way off. It was not backfiring or running rough it just sounded different. After about 10 minutes of mowing the engine bogged down and almost died. I shut the blades off and it kept running but was bairly running, like it was being bogged way down. With the blades dissengaged it stayed running but sounded like it was going to die. I turned the key off to shut it down and the engine sped up to almost normal with the key in the off position. After about 5 seconds it started to shut off as it should. I then moved the key back to the on position and it continued to run but was really bogged down like it was earlier. Then when I would turn the key back to the off posistion and the rpms would go back up. It was not normal but it was running at almost full speed. The engine will run for 5 seconds or so in the off position before it started to shut off.
I replaced the ignition switch thinking this would be the problem. With the engine cold and the new switch in I started the engine. When I started it the egine was still not running right, when I turn the key to the off position it runs a little better for about 5 seconds then it will shut off. Looking for any ideas as to why the engine would run smoother with the key in the off position for several seconds before it shuts off. It does not sound like it is dieseling with the key off, it is not back firing or running backwards it just speeds up for 5 seconds or so.