JD 445 Stumbles when hot (FI)

[GTOJohn]

I have read a lot of the other threads here on this topic and have followed all of the suggestions, but am still having problems with my mower.

The Problem:
The mower starts fine and sometimes stumbles a bit when cold. I can engage the deck and mow grass for 5-8 minutes and then the mower bogs down and dies. If I disengage the deck the engine will run well enough to limp back to the garage but stumbles significantly.

Here is what I have done so far:

• Air Filter replaced
• Fuel Filter replaced
• Spark Plugs replaced
• Coils and plug wires replaced
• Fresh fuel and FI cleaner added
• Air Temperature Sensor replaced (Resistance out of acceptable range)

I suspect that the problem is related to heat. The mower runs fine for awhile and with the deck engaged until the temperature gauge moves up to about 1/4th of the way up. So, on a hotter day, the mower gets to the point of stumbling quicker than on a cooler day, but in both cases it happens when the water temperature gauge is about the same point. The mower is a 1996 model and I have almost 1100 hours on it.

Additional things that I checked include:

• Resistance checks for MAP and Water Temp Sensors
• Loosened Fuel Cap

I'm open to suggestions as to what I need to check next.

Thanks,
John

 

[GTOJohn]

Also, I understand that there are diagnostic codes that may be displayed? How do I go about reading them?

 

[beenthere]

GTOJohn
Still having the problem, or have you discovered a fix?

Kind of left you hanging out there, with little help.

 

[GTOJohn]

GTOJohn
Still having the problem, or have you discovered a fix?

Kind of left you hanging out there, with little help.

Thanks for the follow-up. The problem ended up being a stuck intake valve that led to the pushrod coming off of the rocker arm. An old timer worked on it and he said that the root cause of the sticking intake valve was from deposits that were a result of running fuel with methanol. He suggested that I try to find methanol-free gasoline to run in the tractor, but I haven't been able to locate it yet. He pulled both heads and cleaned everything up and replaced the valve seals. The tractor is running great now.

John