JD 425 carb rebuild?

:x My "97 425 has been acting up this year and most of last year. The symptoms are these, but they are all sporadic:

1.) With throttle set 2/3rds and choke closed, it sometimes cranks for 5-10 seconds before she'll start. then when it does start, it will run kinda rough, sometimes sputter and maybe backfire. This thing used to start instantaneously, I could open the choke right away, and it would run smooth.

2.) After being completely warmed up, it will occasionally start to sputter when mowing and lose power, sometimes backfiring. I'll have to disengage the deck, and play with the throttle to keep it alive. Sometimes it will die, but I can always get it to start and complete the mowing.

I am religious about maintenance, the plugs are good and the air filter clean. Fuel filter is new. Valves set correctly. I have always added STA-BIL to my gas. This year I am adding marine STA-BIL because of the 10% ethanol we have been forced to put up with in our gas. I'm thinking this is probably a carb issue. Tractor has about 670 hrs. on it.

Whadda ya think? Is there a decent carb rebuild kit made for these with the correct parts needed? I just rebuilt my V4 motorcycle's carbs so I'm thinking this would be a relative breeze, to clean and rebuild the carb on this. OR, should I be looking for a problem somewhere else?

Dan the carburetor parts from Deere consist of the
gasket kit,and needle separate.Hard to really say
about it running the way it is.Cleaning the
carburetor would be a fine place to start.I must
ask you has the camshaft ever been replaced?The reason i
ask it could be a timing issue causing poor
performance.That engine was born with a composite
camshaft gear that has failed on many of those
425,445 tractors.I know b/c i have changed a right
many yrs. ago.Just to give you a little history on
the situation.A heads up if you will.I have seen
them fail with low hrs. and i have seen them fail
with over 1200 hrs??Ignition coils were a failure
point as recall as well.Good Luck.JT in NC

Those carbs work in relation with a couple of sensors in the
air box/intake. I would be taking a close look at the wires
going to them as over time they rub and short out. And yes,
you are drawing close to a new cam if you haven"t already.

Also, the time delay module thats on the left side of the engine can cause such problems also. and can be sporadic and intermittent. It too can mess up the timing.

If his has the old style with the square box, I"d definitely consider replacing that module with the newer round style one.

Great points all, thanks guys.

I am aware of the cam issue on these, how does that problem usually present itself? I'm thinking if that is the current problem that it wouldn't be sporadic in nature. Still, it might not hurt to tackle that job one of these days just to be pro-active. Sounds like a good project for the off-season, assuming I make it that far.

I will definately check the wiring to the sensors also, to make sure that's not a problem. Ditto for the time delay module.

The cam will be a sudden issue. Usually they run fine, then
the next time you go to start it it won"t fire. Ie it will happen
on shutdown and you won"t even know it. Please post what
you find when you find it. Tim

Thanks Tim,

I should be digging into it in the next couple weeks. I will post on the results.

Funny thing, I stopped in at one dealer today and asked about a carb rebuild kit. Dude says he can only sell me a complete carb - $300. No o-rings, jets, gaskets, etc. available. Something about JD has new carb now because of EPA and won't sell parts for old carb.

Called a different dealer when I got home. He says take it apart and clean it, if you need any parts he can order them. Go figure but I think I'd call BS on the first guy.

That is bs allright. I work at a dealer and fixed one last week.
Parts are readily avalible. I will never understand why some
dealers lie about things like that. That"s a good way to drive
away customers
Tim

I am having same problems. Did you figure it out?