John Deere 425 Intermittently Running Rich

A couple of years ago I bought my sister a used 20 HP Kawasaki powered Deere 425 from the Deere
guy to replace her old MTD rider. Paid about $4,000 and in the past year it's been back to the
Deere guy a couple of times because it wasn't running on one of its two cylinders. She can't
find the paperwork as I type this, but I remember at the time that they changed at least one of
the ignition modules and had the engine out of it a couple of times. About $2,000 and another
$2,000 when she had them pick it up because it was still running like garbage. That's about an
$8,000 garden tractor now. Anyway I was over at her house a couple of weeks ago and had never
ridden it and she was busy and the lawn needed it's first cut of the year so I had her show me
how to operate the little guy and away I went. A few times while into the cut I noticed the
engine bogging down and wanting to stall and a couple of times did stall. I tried to keep an eye
on when it was doing it, what was I doing when it happened. The following week I wanted to mow
her lawn again to get a better handle on when it was happening and the frequency increased from
the week before.

What I noticed is that it's when the 60" mower is engaged and seems to happen on tight turns,
especially on downward angles on her sometimes two acres. Most of the time it seems that I can
get it to recover by turning the tires straight. A couple of times it has stalled completely.
The 425 Deere is all wheel turn/steer, so I was thinking maybe something related to a/the
hydraulic pump...maybe a filter clogged and causing the engine to bog while trying to push fluid
through it, but since they split it twice I have to assume that changing a/that filter had to be
part of the job at least once since they had to put the hydraulics back together and fill/bleed
it. And then on downward angles seems to play a big part in it most of the time like clock work,
so that makes me think fuel system...maybe something like a float in a carburetor but I don't
know that it even uses carburetors and haven't had a chance to dig into it. One time when it
stalled it shot about a two foot flame out the muffler, so that would certainly indicate a fuel
build up. It does NOT run rough while operating it until it starts to bog down. There is no
miss or dead cylinder at all and when it happens as near as I can tell, its both cylinders
because it wants to die completely and does at times. If it were just one cylinder, I assume
that it would just run like garbage because would be running on one cylinder instead of two, but
it seems to be the whole engine.

It holds a good five gallons and the tank was nearly empty when I filled it and the gas was
fresh, so it's not the gas itself.

For now she still has the 20 HP ONAN MTD and can mow with that because I don't want her to use
the 425 until it gets figured out so as not to cause any damage. I'd like to figure it out and
fix it so as not to take it back to the Deere guy for another $2,000. Any ideas? A Kawasaki
powered garden tractor isn't my forte'. I'm sure that it's a nice little tractor when it's doing
what it's supposed to when it's supposed to and not being a money it.

Thanks in advance.

Mark

I'd check the in tank filter, pump and short line from the filter to the pump.

remove the rear wheels, makes getting the bolts holding the fender deck to the footrest easier to get to. Then remove the seat and two bolts holding the fender down and remove it. Now you can remove the pump from the tank, its right beside the filler neck.

I agree,the line in the tank will crack and or break off. It seems a 1000 hr is a good time for it to happen.

Thanks fellas. I will give that a try.

Mark