PT425 Stall/Loss of Power

[plottamus]

Hi Fellow PTers,

Has anyone ever stalled out while in use? I was mowing yesterday and everything was going great then suddenly I lost all power... chug chug chug then stalled out. I said to myself, "there's no way I went through a full tank of gas already." So I checked the tank and it was still 3/4 of the way full. Checked the air filter and all was fine also. Anyway, it did the same thing a few more times but I finished the mowing job. I found that when it seemed like it was going to happen again, I'd cut the PTO, decrease the throttle, then turn the key to off. I'd sit for a minute or two then go back to mowing.

Any help or ideas would be great to hear before I bother Terry at PT.

Thanks.

Pete

 

[MossRoad]

What engine is in it?

I had a similar chug chug die on my PT425 with the Koehler engine. Turned out to be the nut that holds one of the rocker arms loosened up, and the rocker turned sideways a bit, and that allowed the push rod to pop out. So I was only running on 1 cylinder.

I removed the valve cover, checked the push rod for straightness, put it all back together following the torque settings from my repair manual, and it was fine.... except I broke off one of the valve cover bolts and it still leaks to this day.

A couple months later, it did the same thing on the other cylinder.

Anyhow, that was jus my issue.

Your's could be anything.

Does it sound like it's running on 1 cylinder?

 

[TwinOaks9]

I have a PT 425 with a Robbins, I experienced the same symptoms just before my coils went out, seems as when the coils got hot they started to fail.

 

[m5040]

I had the same thing on my PT018, it was the fuel filter.

 

[plottamus]

@MossRoad It does not seem to be running on one cylinder. I'd hear a miss firing/popping sound and I'd feel the decrease in power, correct? It is indeed the Kohler engine (purchased the machine in 2021 from PowerTrac).

One thing I just noticed was some hydraulic oil dripping on the toe of my right boot. It's a slow drip. Seems to be coming from the Lift/Tilt Valve Assembly. I have not yet diagnosed or pinpointed where exactly the leak is. Could this leak have any relation to the stall/loss of power that was experienced while mowing last week?

Thank ya

 

[MossRoad]

If it was running on one cylinder, you'd probably feel it.

Hydraulic oil dripping from the valve bank probably would not affect engine performance. Just be sure to check the level in the hydraulic tank to make sure you're not losing a lot of it. I had a leak from my steering valve that did similar. Turned out to be just a hose fitting that needed to be tightened.

A 2021 with a Kohler... is that a carburetor or fuel injection?

 

[ponytug]

I had a similar leak in the valve bank, and it was just a loose hose fitting. For the first couple of hundred hours, I made it a habit to gently wrench up hose fittings, especially the small ones. I haven't done it more than once or twice since. Like @MossRoad, I had one on the steering weep oil as well.

@plottamus I wonder if the your issue is fuel starvation; perhaps vapor lock due to running winter fuel in warm temperatures?Or a piece of debris in the fuel line intake, or perhaps fuel pump issues?
You might want to poke through some of the older threads;

Caution to the Kohler Commands folks...

The fuel pump on my CH-25 has now failed twice in about 1300 hours on the meter. Each time, the damaged pump diaphragm has allowed gravity feed from the fuel tank to fill the crankcase with gasoline. After paying $100 plus for the first OEM Kohler replacement (because you must replace both the...

www.tractorbynet.com

All the best,

Peter

 

[plottamus]

@MossRoad it seems to be carburetor... the owners manual states that a high altitude carburetor kit is required when operating above 4000 ft. I still need to fully familiarize myself with the engine... the owners manual does not have a full schematic so I'll need to download. I wish I knew more. This machine is my first that I have to service and diagnose on my own.

@ponytug I'll keep troubleshooting. Thanks for the link and tips.

I've ran the machine a few times this past week... moved some gravel with the bucket and a pallet with the forks. It functioned fine. I have to mow again tomorrow or Wednesday before the rain so we'll see what unfolds.

Pete

 

[MossRoad]

@MossRoad it seems to be carburetor... the owners manual states that a high altitude carburetor kit is required when operating above 4000 ft. I still need to fully familiarize myself with the engine... the owners manual does not have a full schematic so I'll need to download. I wish I knew more. This machine is my first that I have to service and diagnose on my own.

@ponytug I'll keep troubleshooting. Thanks for the link and tips.

I've ran the machine a few times this past week... moved some gravel with the bucket and a pallet with the forks. It functioned fine. I have to mow again tomorrow or Wednesday before the rain so we'll see what unfolds.

Pete

Most Kohler manuals are available free on line. Of course, I paid for mine a few years before everything went free.

 

[ponytug]

@MossRoad it seems to be carburetor... the owners manual states that a high altitude carburetor kit is required when operating above 4000 ft. I still need to fully familiarize myself with the engine... the owners manual does not have a full schematic so I'll need to download. I wish I knew more. This machine is my first that I have to service and diagnose on my own.

@ponytug I'll keep troubleshooting. Thanks for the link and tips.

I've ran the machine a few times this past week... moved some gravel with the bucket and a pallet with the forks. It functioned fine. I have to mow again tomorrow or Wednesday before the rain so we'll see what unfolds.

Pete

Are you operating at over 4000'?

All the best, Peter