Walker 26EFI fouling plugs, the front

[salemtiger]

plug fouls somewhere between two to five hours of run time, it is always wet and most of the time has a carbon deposit across the spark gap, I throw in a new plug and continue to cut. The mower does not use oil, it has 452 hours of run time on the engin. Any ideas as to what the problem is?
Thanks for your :help:

[MBDiagMan]

The first thing to check is fuel pressure. I have no experience with this particular engine but I do know Electronic Fuel Injection and that would be the first thing to check. If fuel pressure is in spec, is there a way to draw trouble codes like there is on a car? I fully expect that there is.

Good luck,
Doc
ASE Master

[Restrorob]

is there a way to draw trouble codes like there is on a car?

Good luck,
Doc
ASE Master

I'm not sure on a walker but on Dixie Choppers there is a small red light along side the ignition switch. Turn the key on and off quickly three times and if there are any codes stored they will flash out on the light.

[Dirty Water]

Car mechanic here, take my words with a grain of salt.

Restrorob: Do these small EFI engines have a o2 sensor or do they run off a fuel table stored in the ECU...Or do they do both?

On a car engine, the sensors to check would be the Throttle Position Sensor, the Intake Air Temperature Sensor and the o2 sensor.

[lawnmaniac883]

Relatively sure that there is a fuel map/table stored in the ecu. I am not positive on this, but I dont see why they would need anything aside from a basic fuel map on these mowers that usually only see one operating rpm?

[Brianslawn]

yes they do have o2 sensors. fuel pressure should be 39-40 psi. you can get fuel pressure sensor from parts store and put on in-line to check. also the o2 sensor is same as 90 chevy 1/2 ton at auto parts store. does it have new style round muffler or old oval? does it have ground upgrade kit? is orange mil on? yes, turn key 3 times to check codes... off-run-off-run-off-run. dont start it though. count flashes (2 sets). 6-1 is at the end. if thats all that flashes... then no codes present. does it run rough or smoke at all (rich)? also there is a computer program you can use to hook your laptop to the mower and moniter it while its running.

[Restrorob]

it is always wet and most of the time has a carbon deposit across the spark gap.

This sounds like a sign of a blown head gasket between the oil return port.Although it is not as common on the 28's as with the 25's it is still possible.
I had a Commercial unit come in yesterday with a loss of power.(running on one cylinder) I pulled the plugs and found wet carbon build-up on one plug, I have seen this well over 20 times (stopped counting) and found this to be the problem. I would suggest performing a simple leak-down test to eleminate any internal mechanical problems before jumping into the somewhat complex engine management systems.
This was also advised by Kohler Technical when this engine was introduced into the market.

[Cobra Jock]

plug fouls somewhere between two to five hours of run time, it is always wet and most of the time has a carbon deposit across the spark gap, I throw in a new plug and continue to cut. The mower does not use oil, it has 452 hours of run time on the engin. Any ideas as to what the problem is?
Thanks for your :help:
I had the same problem recently and it ended up being the fuel pump. Dealer replaced it and the mower runs fine now.

[fixer67]

The codes are accessed through the key switch and
displayed as blinks or flashes of the MIL. Access the
codes as follows.
1. Start with the key switch off.
2. Turn the key switch on-off-on-off-on, leaving it on
in the third sequence. The time between
sequences must be less than 2.5 seconds.
3. Any stored fault codes will then be displayed as a
series of MIL blinks (from 2 to 6) representing the
first digit, followed by a pause, and another series
of blinks (from 1 to 6) for the second digit.

Kohler service manuals are online for free download at the Kohler web site. Below is part of one of those manuals.





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