Shim up the seat switch.

Thanks, Bill. Good thinking, but I should have noted that I have the seat switch temporarily jumpered out. Something else I need to fix properly!

What's the Sears 917.xxxxxx number? Maybe I can find a schematic to look for likely spots?

Is the wire to the carb fuel solenoid snug?

Check the float setting in the carb. It should be level with the carb body. Remove the top of the carb and invert it to check the float level.

Its 917.276020. Seems like ideas are pointing to the carb, so I will have to check that out first.

Thanks for the help!

I can't imagine a left turn leaning the mower over so far as to affect the carb.
I'm still thinking intermittent wiring.

Try- wiggling the PTO knob during both "flat" and the problematic" mowing to see if something "different happens.
Check the plug on the Operator Presence Relay for tightness.
The relay looks like this-

{{gwi:322895}}

It'll have terminals marked 30, 85, 86, 87 & 87A.
The GREEN wire to terminal 85 is the suspect one.
It goes from the ignition switch, "through" the seat switch and to the relay.
Also make sure the black wire(s) from 30 & 86 have a good ground.

That relay is known as a "Bosch" relay and is very common.
Car Stereo stores use it for high powered AMPS. Also High/low beam switching on head lights.
It's about a $4 part at an auto parts store and $16 at a "tractor" store.

Also, recheck your "jumper" on the seat switch.

Thanks for the tips. I will double-check that jumper. I want to get that switch working properly - or else I may be absent-minded some day with unpleasant results.

I already replaced the seat switch itself because the previous owner hacked up the original when he defeated its function. The new switch was not sensing me on the seat, so I jumpered it out temporarily to get some mowing done. I assumed the plate needed adjustment, but maybe it is that relay or associated wiring, and the problems are related.

At any rate, thanks much for the ideas. I know how I will be spending part of my weekend!

And I hope in future I can be of similar assistance to others!

I replaced my solenoid - #145673 - and fixed the same problem.

"I replaced my solenoid - #145673 - and fixed the same problem."
So how does replacing a starter solenoid fix a problem on an engine that already starts?
I'm REALLY curious!

Have the exact same problem as Nmce with my Craftsman DGT6000/ Kohler 26hp. Please save me some time... did Nmce find a resolution? I am where he was when this thread started. Seat switch jumpered. Unlikely the carb since the engine runs great under heavy load and only cuts out in turns and the occasional straight Heavy bump. Any help is appreciated... Thanks!

Post the Sears 917.xxxxxx.
Not all Sears schematics are the same, so not all solutions are the same.

sears model no. 917.276380. Thanks! Any help is appreciated.

I have the schematic for that, since Sears has the manual online-
http://www.managemyhome.com/mmh/lis_pdf/OWNM/L0503415.pdf

Not sure what you mean by having the seat switch jumpered?
On that tractor, there is continuity through the switch when unoccupied. It also has a shorting connector, so when you pull the plug, it maintains continuity.
Basically, anything that grounds the M terminal of the ignition switch will kill the engine.
My main suspects would be the seat switch and the reverse switch. I think I'd check the adjustment of the reverse switch first. It may have "marginal" engagement and slight flexing of the tractor frame might be enough to do the rest.