L4240 Stalls when the ambient temp is hot.

[kleetus]

went out last night and tested the seat switch, and it still stalls with the seat up, idling with the PTO running and not running.

got up early this morning and mowed 3 fields, no stalls at all (took 2.5-3 hours). Soon as it got over 75, it starts stalling.

the only way I can replicate it, is to run it when ambient temp is warm

 

[JWR]

This is wild... hard to figure. This is out in left field BUT has it ever been overheated before , especially for any period of time or very severely? I know of a Kubota 3 cyl that seemed to overheat a lot, people thought that was cured, and tht had gone on for months. When it was taken in for serious shop investigation we found that the engine had seized temporarily at times of extreme overheating. Users had been fooled by the temp gauge (which doesn't work after the coolant boils away.) To shorten the story th end result was not just a blown head gasket but a cracked head. And it was overheating much more when the outside air temp was 95.

 

[kleetus]

no it has never over heated. it stays at 4 bars once it warms up. I had considered the gauges but I dont really know how to test a gauge so thinking about it is as far as I got.

no lights come on, no errors, no smoke, no beeps.

 

[Harry in Ky]

Check your PM inbox.

 

[seville009]

Two things I would try/check:

The next time it starts to stall, completely remove the fuel cap (instead of just loosening it), and then just let it sit there for a bit without reducing the throttle and see if the engine goes back to normal.

Even though it’s been serviced, pull out the air filter and check it over. Also get into the complete air intake system (before and after the air filter) to make sure the entire duct work is free of obstruction.

 

[jonsstihl]

Have you actually pulled the radiator cap and visually verified there is coolant in there. With the engine cold of course.

I'm assuming the tractor starts and runs even when ambient temps are higher but that it stalls when engine temp gets hotter. do you have an infrared thermometer you could take a couple readings with...

I don't think that model has a lift pump. it is gravity feed to the fuel filter housing. no turbo and no EGR. I am leaning towards electrical. maybe something is causing that fuel shut off solenoid to activate.

 

[jonsstihl]

I would clean out the radiators really well with air then water to make sure it is not actually overheating. maybe there is a protection when the temp gets too hot independent of the gauge.

 

[kleetus]

Have you actually pulled the radiator cap and visually verified there is coolant in there. With the engine cold of course.

I'm assuming the tractor starts and runs even when ambient temps are higher but that it stalls when engine temp gets hotter. do you have an infrared thermometer you could take a couple readings with...

I don't think that model has a lift pump. it is gravity feed to the fuel filter housing. no turbo and no EGR. I am leaning towards electrical. maybe something is causing that fuel shut off solenoid to activate.

I have personally removed the radiator cap and verified its nice and green and full.

its not when the engine gets hot, I mowed for 3 hours this morning when it was cool. once its warm I can go out and it will stall right away. But yeah I can check it with an infrared. When I say hot I mean 80 btw.

I also checked the battery and its putting out 12.75v

Tomorrow I will check the air lines and see if there is anything in there. I have checked the filter already.

The tech was here today and has never heard of this happening, he's going to run it by the Kubota rep..

Maybe this is "the force" telling me its to hot out, and I should be resting..

 

[JWR]

Let's hope there is no such thing in tractors BUT, the major auto/truck manufacturers all have systems that sense potential major damage to the engine or the transmission and put the vehicle into "Limp Mode." Most of the time turning off the ignition and restarting clears the issue at least temporarily.

I would do a pretty quick search of your manuals (and ask the brightest tractor mechanic at your dealer) if Limp Mode exists for your specific tractor model.

 

[kleetus]

well after a few weeks of cool weather, it finally got warm. Tractor was running good while it was nice.

On the first hot day it started stalling pretty bad, when I got back to my shop there was hydraulic fluid coming out of the silver thing (or above it and dripping down) in the pic. Service folks said it most likely some seal on the transmission in there that doesnt go bad often.. of course. I dont remember exactly what he said it was, but required essentially split in half.

Havent heard back yet on the exact issue. But I am guessing the stalling was when the fluid got to a certain temp it would start to leak then stall out.