Could be a bad coil?
They will act like that some times.

Joe

 

So all the symptoms you list.. How about some more info..

What is the engine temp? OK or Hot? Smell the engine oil.. Does it reek of gas? that's bad news if so.. Lets move along..

Test the compression in the cylinders.. Should be 180# & within 15% if I remember right..

How did the old plugs look? One different than the other?

Pull the plugs out and ground them against the heads (anything metal) and crank the engine.. What color is the spark? A good ignitor and coils will have a nice crisp blue/white spark.. if it's red or orange on one side check out the coil / pulser on that side..

If it's red or orange on both sides the culprit is most likely the ignition module.. Swap in the old one and test.. (just plug it in.. don't need to ground it)

If the spark is better, pop the top off the carb (close the choke so you don't drop anything in the bore) The fuel level should be about 1/4" under the carb bowl. Pop the float out and give it a shake.. Any fuel inside the float? Replace it..

The electronics on these are a bit to get your head wrapped around but the service manual has detailed wiring diagrams and troubleshooting help.

Hope this gives you some help..

I know just how frustrating the 425 is! My deck kept cutting out a week or so ago.. I replaced the usual culprit- PTO switch but it still didn't work.. After much cussing and fiddle-farting around I found a dirty connection on the control panel.. Back in business now..

 

These are longshots, but is there any chance the rubber intake hose to the air cleaner is collapsing when hot and choking it out? I am not sure what choke system the Kawasaki uses, but could it be activating?

 

It's got a manual choke Tim.. If the hose isn't inserted into the side panel it could be an issue though..

I think you should just send it down to WNY and let me fix it! :smilewink:

 

So all the symptoms you list.. How about some more info..

What is the engine temp? OK or Hot? Smell the engine oil.. Does it reek of gas? that's bad news if so.. Lets move along..

Test the compression in the cylinders.. Should be 180# & within 15% if I remember right..

How did the old plugs look? One different than the other?

Pull the plugs out and ground them against the heads (anything metal) and crank the engine.. What color is the spark? A good ignitor and coils will have a nice crisp blue/white spark.. if it's red or orange on one side check out the coil / pulser on that side..

If it's red or orange on both sides the culprit is most likely the ignition module.. Swap in the old one and test.. (just plug it in.. don't need to ground it)

If the spark is better, pop the top off the carb (close the choke so you don't drop anything in the bore) The fuel level should be about 1/4" under the carb bowl. Pop the float out and give it a shake.. Any fuel inside the float? Replace it..

The electronics on these are a bit to get your head wrapped around but the service manual has detailed wiring diagrams and troubleshooting help.

Hope this gives you some help..

I know just how frustrating the 425 is! My deck kept cutting out a week or so ago.. I replaced the usual culprit- PTO switch but it still didn't work.. After much cussing and fiddle-farting around I found a dirty connection on the control panel.. Back in business now..

When it acts up the engine is at normal operating temp. The engine oil is fine no strange smells. The old plugs looked the same. The one time I had chance to work on it when it acted up the plugs were damp flooded with gas. I havnt checked spark when it was acting up.

Question. If its not getting good spark it would almost act like its flooding. Would not be burning clean and could fool me into thinking its fuel related when it could be spark problemm?

 

Sounds almost identical to the symptoms of the bolens with a kt19 series 2. It would run fantastic. Then it would start missing. Then it would start shutting down. If you caught it before it shut off you could fill choke it and it would idle super rough but wouldn't stop for a bit. Then it would load up and die. It wouldn't do anything for an hour or so.

I chased fuel problems. I was off base.

Put a new coil on it. Perfect.

 

I brought this tractor home the other day. Pulled the plugs before I started mowing and the are black, I tested the spark seemed ok. I started mowing and it ran fine for about 45 minutes then it would miss a little but clear up. After another 15 minutes it was losing power and sputtering. I turned mower off headed for the garage. It started to surge and smoke black. I shut it down and pulled the plugs. Smelled of gas. I was going to test the spark again. When I turned the engine raw gas came out the hole. (Lucky it didn't ignite as I was holding the plug against the head.) Choke is addjusted properly and is off it doesn't creep or work its way on.

Why would the carb be flooding that much. This model has the solenoid shut of on the vacuum hoses. (my 425 has the shut off solenoid in the baseof the carb)

I put a carb kit in this winter and its doing the same thing as before.

Thoughts???

 

Interesting problem.

I am wondering about the coil/s shorting out after it gets heat-soaked.

 

From another forum

Welcome to the thread.

First, it sounds like the float level is set too high, allowing too much gasoline into the carb.

The needle and seat in these machines are very negatively affected by the fuel now sold at the gas pumps which has Ethanol Fuel blended in it. The ethanol will crystallize and turn almost sugar like inside the fuel system components and not permit the needle valve to full close in the seat, which means more fuel than you need and fuel continuing to flow.

The fuel pump pumps a static amount of gasoline, when its running. Your system does use a control valve, shown as number 11 in the illustration. Make sure this valve is functioning and isn't plugged open. You may want to ask your dealer if this is a commonly replaced item and if it is, replace it if you aren't 100 sure its working correctly.

I would make sure the float level is set correctly. With the carb being 3 years old, I would replace the needle and seat with a good quality part. Unless you inspect it with a magnifying glass, you might not see the issues which are impacting the needle valve and the seat. 3 years of use with ethanol fuel is a LONG TIME.

Once you get the issue resolved, I would make it a practice to shut the fuel shut off valve and allow the tractor to run itself out of gas if you are going to be not using the tractor for more than a couple of weeks. This will run all of the gas out of the carb and help to reduce the ethanol problems in the fuel system. Plus this will keep the valve freely operating.

Your float level is likely too high, allowing too much fuel flow. The difference could be as small as a few thousandths of an inch. Between installing a new needle and seat ( BOTH PIECES) and setting the float level, this is where I would begin.

Also, there are different carbs used on the 425 so make sure to take your tractors serial number and the carb for the specific markings to make sure you get the right parts you need. This is very important......

I would purchase a new float and needle and seat and gasket set just to be safe. You can use the old float, but if it were mine, I would replace the needle and seat and float just to be safe. In this illustration it is the kit shown as number 8 but I would make sure you get the right parts based upon the serial number and the carb numbers.

Check out this link for the differences. Go down to the carbs and you will see the different series numbers.

 

The valve adj is a good start.The fuel flooding could be a couple different things and on these older 425's it can be a problem.I had some issues with flooding on mine (94 model) and there were several steps I took to correct it.These early model 425's had a different system for venting the fuel tank than the later models did and it gets a little complicated so I will do the best I can to try and explain it but you may need to look at a service manual to really understand it.They had a non vented fuel cap and a seperate vent coming off the fuel line up under the fender pan,then there is a carburetor vent solenoid attached to the air cleaner base with 3 vaccume lines attached to the carb and air cleaner.The vent solenoid when it works properly stops the carb from siphoning fuel after shut down which they will tend to do and maybe causing your flooding problem.The steps I took are as follows,I eliminated the funky vent system on the fuel line and went to a vented cap used on the latter models,I hooked the vent solenoid back up on the carb after bench testing it to make sure it worked correctly (PO had by passed it).The I took it a step farther,I installed an electric inline fuel shutoff on the line close to the carb,it is a simple device that I wired to the key switch on its own fuse key on allows fuel to flow through the line,key off shuts off fuel flow.I also lowered the float level slightly in the carb.I did these mods on mine 2 years ago and it has been great since,it took me awhile to figure out this fuel system and understand it.

 

This is interesing

https://www.houzz.com/discussions/1638799/john-deere-425-mower-problems

 

This is interesing

https://www.houzz.com/discussions/1638799/john-deere-425-mower-problems

Plugged radiator fins is possible but the temp is ok..

You said the spark is OK.. Blue white or orange red? It makes a difference..

You could be losing a cylinder after a while which is classic bad coil symptom.. But the engine should run on one cylinder.. And it doesn't.. that leads me to believe the module is at fault.. Did you swap out with the old one?? Electrical connections- The thing is old so clean them all out.. I put dielectric grease on all of them before putting them back together..

The service manual gives a detailed test to check out the coil in the electrical section.. PM me for more..

 

I changed the spark control module. Although I had tried that before with no luck. The spark does seem crisper if that makes sense. Of course by tthat time I was almost done mowing. I will have to wait for the grass to grow before I will know if that was the problem.

Good news is it started raining last night which is really needed. The crops were looking good but the hay and grass land needed rain. My lawn hadn't been mowed in just about 2 weeks while it was shaggy and looked better after being cut it wasn't out of control.

 

With new spark control module, after mowing about 1 1/2 hours it started to sputter and act up again.

I blow out the rad every time after I mow, temp gauge runs most time in the bottom 1/3 of the gauge.

I think I am going to swap carburators. Although I just put a kit into this carb. Tthis carb has the shut off on a vacuum setup. I keep seeing comments that these carbs can act up. My other tractors have the soleniod in the base of the carb and have not given me any issues.

 

Watching this to learn as my brother owns a 425.

 

Watching this to learn as my brother owns a 425.

They are a great machine. I have one with 2100 hours (When I bought it had about 1000 hours) and it works great, strong tough little tractor. This one of my sisters is giving few issues at 700 hours. Its well worth the time to figure out.