It isn't the ethanol in the fuel that caused the problem, it was varnish in the fuel bowl. When you added the ethanol-poisoned fuel, it loosened up anything that was safely "stuck" to the bowl and is now clogging your jets.

I have a GCV160 on my Honda pushmower and it is a fantastic engine if you keep the carburetor cleaned out. Drop the bowl and clean out the jet in the nut that comes off with it. That should get you going again. When you're finished mowing, shut off the fuel valve and run the engine until it dies. Been doing that with poisoned fuel for 6 years and not had to clean the jet since I started doing it.

Make sure your TroyBilt mower has a shear-key on the blade hub. Honda pushmowers do not (STUPID STUPID STUPID STUPID IDEA), meaning if you accidentally clip the curb like I did, you now have a bent crankshaft.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]