JD 425 hard starting cold, starts fine hot
I've been having a recurring problem with my 425 w/ Kawasaki FD620D motor, it will sometimes start cold, but the vast majority of the time, and it's getting worse, it will spit, sputter, backfire thru the exhaust, shudder and after so much cranking you'd think the starter would burn up, it'll finally start, even then sometimes it will quit and have to restart, and sometimes it will run fine. If you choke it, even for a second or two, it's flooded beyond belief, then a backfire thru the exhaust and repeat cycle. Warm, the thing runs like a banshee, never a problem, with plenty of power. Well, if you have this problem, I'd like to hear the fix.
For me, I checked the fuel shutoff solenoid and it was working. So, because I mow over 5 acres around the two houses I own next to each other, I decided not to fiddle with it, and I checked the plugs, looked fantastic, checked the valves, lash was good, and since it runs strong and fine when warm, and will start with just a blip of the key when warm, I surmised that fuel delivery on startup was the problem. I have two full sets of fuel pump/gas gauge setups that I had tried to no avail, both did the same cold start routine. Soooooo, I bit the bullet and bought a new carb from the local JD dealer and wooohooo! it seems to have fixed it big time.
Before i put on the new carb, of course it started right up with a blip of the choke. I only ran it for 30 sec or so to move it into the light. Changed the carb, and forgot I had the choke on so as to not drop anything down the carb throat, and it fired instantly. Choke off and it started right up. Let it set for 45 minutes, no choke, started right up instantly. So I think it's fixed, but time will tell. One interesting thing when I was looking at the old carb, the fuel shutoff now will not work. I tested it by putting it across a battery and no pull in. So maybe it was part of the problem, but the tractor shouldn't run at all with it not opening? right?
Anyway, if you've had this problem, I'd like to know if anyone ever nailed it down exactly. I haven't had time to do an autopsy on the old carb. I'd had it apart a few time monkeying with float levels to see if it made a difference, and it did not, so I just dunno.