Puzzling problems with engines just stopping

[davem1111 2,311]

I posted recently in another thread about having this problem with my 416-H but can't find what I wrote.  Basically, when I'm mowing with the 416-H, it runs great for 10-15 minutes, then it just dies. Sometimes it will start again after a few minutes of sitting, but I think what I determined (at least, one problem) is that the charging system isn't working so the battery goes dead, hence no spark. But it also seemed like the coil was getting very hot,  and it was a "non-standard" coil from what I could tell, so I bought a new coil and regulator. Installed those, tractor runs great, but still dies after mowing for a bit. I made sure the air filter isn't clogged, and fuel flow seems to be steady.  Yesterday I even tried putting a car battery on the left running board and hooking it up in parallel, and maybe that helped some but not enough. Tractor seems to sputter when going from forward to reverse with the PTO engaged, so maybe I have some faulty wiring with one or more safety switches?

 

Anyway, the plot thickens. 

 

While giving the 416-H some "cooling off" time, I started mowing with my GT-1848 (with Honda GX610 engine).  Guess what?   10-15 minutes and it died also. After a few times of that happening, I took it in the garage during a short spurt of running. Recently got some new parts for it so I changed the air filter (it was pretty bad). Due for oil & filter changes for engine and trans but didn't do that yet. Checked wiring, etc., nothing out of place. Battery fine, not run down.  WTH?  It was showing some bubbles in the fuel filter while running, so maybe something going on there? I only had time to run it again for a few minutes but I'm assuming that the problem isn't "solved".

 

It's been very hot, but I haven't had problems like this in the past with it just being hot outside.  I need to take the time to diagnose the charging system on the 416-H but am not anxious to tear into the stator, if that's where the problem is. Will do that if I need to. I'm going to be short on time between now and Labor Day though. Still have about 1/3 of the yard unmowed, and it will be a foot tall before I can get to it assuming I have a tractor running long enough.  My 312-A is in pieces because I finally decided to clean that up and do some repainting.... bad timing.  4 decks, only 2 working right now. Sheesh. I need to retire. 

[ebinmaine 79,955]

Is vapor lock a possibility? 

@squonk mentioned a particular type of fuel filter that's more prone than others.  

[c-series don 12,244]

My first thought was plugged vent in the gas cap, causing vapor lock as Eric said. But with two tractors doing it, now I’m confused 🤔 

[squonk 47,585]

Let's see the fuel filter you're using.

[sqrlgtr 3,542]

EMP

An electromagnetic pulse (EMP) is a short, intense burst of energy. It can damage computers, power lines, and electronic devices. An EMP happens because of natural events like lightning or solar flares, or man-made events like high-altitude nuclear blasts. [1, 2, 3, 4, 5, 6]

I suggest a faraday cage while mowing.

 

[Bill D 3,036]

Any chance a mouse got into the engines.  If they overheat they will shut down.

[lynnmor 8,957]

I guess that the 416H has an Onan engine, if so the most likely cause of shutdown when hot is the ignition module next to the stator.  To test, have a spark plug ready and stick it on one of the spark plug wires and hold the threaded end against a metal engine part while cranking the engine.  Do this as quickly as possible after it shuts down and look for spark.  If none, wait till it cools and test again. Those ignition modules can get temperature sensitive with age.  Maybe your other tractor has the same issue.

[rmaynard 17,484]

Pure coincidence that both did it. My guess is what Don said, clogged gas cap vent. Loosen the cap and see how long it runs. If it works, try the GT as well. Stranger things have been known to happen.