Motor stops inadvertently

[Bdent]

Air cleaner indicates it is a FD750D 27hp, the sticker on valve cover shows it MFG date of 07/05, engine family KAXS, 745N4CA. It is in my 2008 Simplicity Legacy Mini Tractor with 1k hrs I am the 2nd owner, It has run fine for me the whole 100+ hrs I have had it. I've Goggled till I can’t Goggle anymore. I was going to change the coils next but I do not think both would quit working at the same time. When it quits running it's like the key was turned off. It will run for 10 minutes when cold, (runs great), let it sit for 5 minutes restart and runs for a couple minutes. It will die at full throttle with the blades engaged and when just trying to baby it back to the garage. I've done all prelems, Vent on gas cap (even ran it loose) new fuel filter (clear with fuel flow), new pump (working to carb) new battery (all connections are clean) (I haven't check the engine ground I guess that's next but does not make sense about it restarting right away). New plugs (looking good but only have 20+ minutes on them. Oil and filter newer (10 hrs) and level good. Someone please HELP. I've got 7 acres of 12" high grass and weeds to mow. I am posting this on the Simplicity thread as well

 

[txmowman]

Junk in the fuel tank getting picked up and cutting fuel flow? Is the fuel pump working correctly? Should flow 6-7 oz of fuel in 30 seconds at between 2.5 - 3 psi. Try gravity feeding fuel directly to the carburetor. These would be my thought. Doesn’t seem electrical if it will start right back up.

 

[Bdent]

No junk in the tank, In original post. new fuel filter shows fuel flow, new fuel pump is pumping. If those were the issue I can only assume it would not run at full throttle with load for 10 or so minutes

 

[Bdent]

in the post, It does not start right back up it has to sit for 5 or so minutes to run for a minute or two, and if completely cold will run for 10m or so minutes. When it does quit it is like the key was turned off. Not like it was running out of fuel.

 

[txmowman]

There is nothing on the engine that is going to reset itself after 5 minutes of sitting. I would focus on the safety system next. Seat switch, other switches.

 

[Bdent]

Thanks for the input, The only reset issue (if one were to call it that)

I can imagine, may be one device that is failing when the engine comes to temperature,

Which would allow or disallow spark to both plugs.

I do not think it is a reset issue, as the time difference between it being cold and running till it stops is 10 or so minutes,

which is different that waiting 5 minutes after a shut down and restart and running for only 2 minutes or so. Both times are somewhat consistent

 

[txmowman]

As you stated, it would be very unlikely but not impossible that both coils would fail at the same time. And, the coil will actually get hotter (heat soak) for up to 5 minutes after the engine stops.

 

[Bdent]

So are you saying there is not one item that controls spark to both coils?

Are the coils not connected to the battery via the regulator?

I am very familiar with 5hp pull start and automotive engines, not these larger small engines

 

[bertsmobile1]

The coils a self energising so they are not connected to the battery and doing so will fry them in no time flat
For the purpose of testing you can remove the kill wires from the coils
The Kawasaki manual shows them as being white while the Simplicity manual shows then as being violet .
That engine has a low oil warning system as well .
On the earlier models it just went to a warning light on the dash but I have a feeling the latter models it was connected to an ignition cut out
So if the oil level is a little low, after a couple of minutes of running the oil that was in the sump gets distributed all over the engine, causing the sump level to drop activating the low oil shut down.
After sitting for a few minutes the oil drains back into the sump so the ignition circuit is good to go again.
I was sure I had a late model diagram I can not find it
Simplicity have all of their manuals on line but you will need to use the model number to get them
Simplicity web page
If you post your full model number off the ID tag
If you post it here as well we can look up your exact wiring diagram so we don't give you a bum steer.

 

[txmowman]

The coils a self energising so they are not connected to the battery and doing so will fry them in no time flat
For the purpose of testing you can remove the kill wires from the coils
The Kawasaki manual shows them as being white while the Simplicity manual shows then as being violet .
That engine has a low oil warning system as well .
On the earlier models it just went to a warning light on the dash but I have a feeling the latter models it was connected to an ignition cut out
So if the oil level is a little low, after a couple of minutes of running the oil that was in the sump gets distributed all over the engine, causing the sump level to drop activating the low oil shut down.
After sitting for a few minutes the oil drains back into the sump so the ignition circuit is good to go again.
I was sure I had a late model diagram I can not find it
Simplicity have all of their manuals on line but you will need to use the model number to get them
Simplicity web page
If you post your full model number off the ID tag
If you post it here as well we can look up your exact wiring diagram so we don't give you a bum steer.

Riding mowers do not have a low oil shutdown. At least not in the US. This is not OSHA compliant.