PT425 Sudden Engine Stopping

[Kaon99]

Hi Gentlemen,
Recently while mowing a walking trail near my house. My 2002 model PT425 Kohler engine suddenly sputtered and died and would not restart. There was about 1.5 inch of gas left, but I still assumed I had run out of gas. Filled the tank to about 1/2 full, but still would not start. I checked the fuel line from the tank through the fuel filter and there was no blockage. At this point I think it is either a carb problem or a fuel pump problem. What would you all suggest checking next? Do you think it is worth a call PowerTrac? I am very hesitant about trying to fix it myself. I am in North MS and so far cannot find a local Kohler repair shop. What do you all suggest? (By the way this is the first problem I have had with the Kohler engine, which has about 500 hours on it.)

On a different topic, I cannot find a replacement code for the fuel filter in the Kohler manual. I think my machine is the same model as MossRoad's. I will check soon and let you know for sure. Would appreciate any info you can give me.

Thanks, Kudzu Ken

 

[Fuddy1952]

Usually when motor dies it's either no fuel or spark.
With air filter off spraying some starting fluid in will rule out fuel.
Spark you could remove one plug, be sure it's grounded (thread side on block), see if it sparks.
My guess is a safety switch somewhere failed.

 

[MossRoad]

The only safety switch on that machine that would make it not start is if the PTO switch is in the ON position.

Don't know about a low oil sensor.

So, some more questions about your machine....

You said it would not re-start.

By that, I ask:
Does the starter spin the engine but it just won't fire?

Or, does the starter not even spin the engine?

 

[Kaon99]

Fuddy1952 and MossRoad,
Starter spins the but engine will not start. Will try some starting fluid. Starting fluid has worked in the past whenever my machine had sat for a long while without being used. When the engine died, it sounded exactly the same as the times when I let it run out of gas. Also, will check PTO switch. I will feel pretty dumb if the PTO switch is the problem! Thanks for the suggestions! Will let you know. - Kudzu Ken

 

[MossRoad]

If your PTO switch was on, all you'd hear is a click when you turned the key. If the starter engages and spins the engine, the PTO switch is NOT the problem.

Trust me, I replaced my starter 2 months ago because of this.

 

[BobRip]

Check the outlet of your gas tank. It sometimes gets trash in it.

 

[Fuddy1952]

Check the outlet of your gas tank. It sometimes gets trash in it.

"I checked the fuel line from the tank through the fuel filter and there was no blockage."

 

[ncstriper]

If you take the fuel line off of the carburetor hang it in a bucket with the fuel valve on. Try cranking the engine and the fuel should pulse out of the line. If it doesn't. I would replace the pump or look for blockage.

 

[tlb]

Hi Ken,
I have a 2002 PT425 as well, and now have starting problem. So any feedback appreciated. I will give a little history of starting problems experienced in the past and what my present symptom appear to be.

A few years after I bot the PT425, had an issue which appeared to be the starter. Replaced the starter but same issue. Ultimately traced it down to intermittent key switch. This took a while to figure out. Replaced key switch with new one and tractor started right up. As Moss mentioned, changing the started is a pain.

I ran into the PTO switch 'on' issue several times. Sometimes it gets flipped to 'on' position by accident so make sure it's 'off'.

My present problem is more complicated. Tractor was starting and running fine, then over the course of several days, it became harder to start. The starter would spin but the engine would take a while to fire up and run. Eventually, it would not fire at all. The starter would spin but just not fire up and run. I changed the air filter and fuel filter thinking maybe bad gas. Next time I tried to start the tractor, the starter would 'click' but the engine would not turn over. Tried a jumper cable from my truck battery to the PT425 battery but no change, starter just 'clicks'. Put a charger on the battery overnight, but no change when I tried to start, starter just 'clicks'. Took battery to autoparts store and had it checked. They said it was fine. Battery is 1.5 years old and still under warranty.

So what might be causing these issues? Starter not turning over engine and engine being hard to fire up. Could be a starter issue or a starter solenoid issue? Maybe another bad keyswitch? Bad fuse somewhere? I had a fuse blow once (in 18 years) which prevented the tractor from turning over. Worst-case, engine seized?
-Tim

 

[MossRoad]

Worst case is engine seized. Let's not go there first.

Since you know the battery is good, suspect the starter wiring first. Take all the cables off the starter and battery, clean up all ends, including the ground, put them all back and try again.

If yes, done. If no, continue.

Suspect the starter again.
Remove the starter and take it to a lawnmower shop to have it tested or find a video on youtube to show you how to make it spin off the machine.

If the starter is bad, replace it again.

If the starter is good, something's preventing the engine from turning.

You should then remove the spark plugs to relieve compression and see if you can get something on a shaft to see of you can easily turn the engine by hand.

If you can, it's back to suspecting the starter.
If you can't, ouch! And we'd proceed from there.

 

[Marks481]

If it was hot... vapor lock in the fuel pump.

Or your fuel pump diaphragm is damaged. Replace your fuel pump. This is almost a consumable item on these engines.

Check your oil level too to ensure it hasn't magically increased (gas in your oil can do that).

 

[Marks481]

Check the outlet of your gas tank. It sometimes gets trash in it.

"I checked the fuel line from the tank through the fuel filter and there was no blockage."

It isn't that obvious, so it is worth mentioning again and again and rechecking again.

Everybody with a PT4XX machine eventually gets trash in the plastic elbow on the bottom of the fuel tank that blocks flow. If you don't know to specifically check that, you will never notice that.

 

[Fuddy1952]

It isn't that obvious, so it is worth mentioning again and again and rechecking again.

Everybody with a PT4XX machine eventually gets trash in the plastic elbow on the bottom of the fuel tank that blocks flow. If you don't know to specifically check that, you will never notice that.

I understand. I was going by him saying he was getting fuel.
Biggest problem now is hopefully motor isn't seized. Otherwise it shouldn't be a big deal getting it running again.

 

[cqaigy2]

Extended cranking with the starter can cause problems with the starter motor. That doesn't explain why it won't start, but i could be another problem that has cropped up. I had a starting problem because of the ignition switch. After i replaced it, i tore it apart and saw the contact looked to have built up resistance over time and caused excess heat and melted the mounting for the contacts.

 

[Kaon99]

Hi Guys,
Let me update things a bit. The engine turns over but will not start. As best as I can remember, when I took of the air filter and choked the engine I saw liquid fuel in the carb. I will check that again. Hope this extra info says something to you. Please let me know if you have any new suggestions. Thanks - Ken

 

[m5040]

I didn't read through the whole post, but I would recommend 1. take out spark plugs (maybe time for new when you put back in, if carboned up they flood easy). With plugs out of cylinders, plug good spark plugs back into plug wires and lay on a good ground on engine. Now crank over. It will turn much faster with no compression. You should see good sparks at the plugs. If so, then put new plugs back in, tighten them up. Then use some starting fluid/either and squirt in carberator intake with engine turning over. If it fires up for a second or two, it is a fuel problem. If it doesn't the engine may be out of time, like a sheared flywheel key (or whatever your engine make used to time the ignition with crankshaft position). Just my 2 cents.