425 slowing on hills

[Modrob]

My 425 has developed an intermittent issue—running fine on level ground/road. Then when I hit a hill (especially my long, uphill paved driveway) it wants to bog down and sounds like the Kohler engine slows to the point of almost dying. If I let up on the pedal, or feather it some, then it seems to “catch” and everything starts “climbing” back up to a normal pace, and speed comes back…
Last night, I was towing a small towable backhoe up the drive, and it bogged down, nearly failing. But again, at the last second, something happened, and it started climbing again…
Any ideas where to start looking?

 

[ponytug]

Does it do the same thing under load against an immovable object?

So, this sounds a little like normal behavior. If it is not normal, and if this is a new/abnormal behavior, more details would help, like temperature (outside, engine, oil), throttle setting(s), etc.

If you know all this, forgive me. PT drive pumps are variable volume; so, the harder you push down on the foot pedal, the greater the flow (faster), but it means that the engine load goes up. So, without added horsepower via added throttle, the engine will bog down. When you need more power, you have to throttle up, and/or feather the foot pedals.

All the best,

Peter

 

[PowerTracManiac]

I had a similar issue on my 1460. Felt like bogging down when going up hill/needing power.
Ended up being dirty fuel filter and the second time dirty filter and bad fuel pump. Couldn't get power when needed cause it was intermittently starving for fuel.
Easy place to start is fuel filter/lines.

 

[Modrob]

Does it do the same thing under load against an immovable object?

So, this sounds a little like normal behavior. If it is not normal, and if this is a new/abnormal behavior, more details would help, like temperature (outside, engine, oil), throttle setting(s), etc.

If you know all this, forgive me. PT drive pumps are variable volume; so, the harder you push down on the foot pedal, the greater the flow (faster), but it means that the engine load goes up. So, without added horsepower via added throttle, the engine will bog down. When you need more power, you have to throttle up, and/or feather the foot pedals.

All the best,

Peter

Thanks much for the info.
Let’s see:
Against an object, yep does it too, but I believe that feels more “normal”…outside temps are HOT and humid—high 80s I believe…throttle wide open or very close…
I do believe I need to adjust the pedal action for forward (been needing attention for long time but just haven’t gotten to it yet)
Yep, I “feather” the pedal when this happens and after about 15 seconds (yesterday pulling that load) I almost drug down to a stop and engine about to stall, but then suddenly it began to pick up, and it quickly built back up, and pulled on up. Like nothing happened…

 

[Modrob]

I had a similar issue on my 1460. Felt like bogging down when going up hill/needing power.
Ended up being dirty fuel filter and the second time dirty filter and bad fuel pump. Couldn't get power when needed cause it was intermittently starving for fuel.
Easy place to start is fuel filter/lines.

I’ll look into this as well. Thanks much for your input.

 

[ponytug]

I also would not rule out vapor lock in your fuel lines if you had been using your PT425 for a bit. There are multiple threads here on it, but basically either rerouting the fuel line, insulating it or both are solutions.

All the best,

Peter