What's wrong?

[ukrkoz]

I have flail mower with this engine:

15 hp 420cc JiangDong electric start
That engine is basically Honda knock off.

Everything worked fine till today.

I towed mower out into the filed, started it, start mowing - after about a 100 ft, it dies. Engine shuts down. Start it again - starts fine. Start mowing - engine sputters and dies.
And keeps doing this - starts, runs fine, start moving, what means - mowing - engine dies. Dies like as if fuel supply cuts off. But don't listen to me.
I tow it back to where it normally parks, check on every thing - all appears to be fine. Start, stand there for few minutes - runs fine. Start towing mower - dies. Starts and starts dying - so on a hunch, I opened gas tank cap. PRMs jump up, engine appears to run fine. Put cap back on - engine dies after some time.
So out of desperation, I leave gas tank cap not fully tight - mower starts mowing. Sounds abit strained, I just go slow, but it mows. Didn't stall even once. Gas cap undid itself several times during 1 hr mowing, but, otherwise, I finished what I needed to do.
Parked mower, tightened gas cap.
So I figure, it has something to do with fuel supply?
Air filter is clean.
I had tank topped before I started mower, but I had same last time, without any problem. Does it have like a fuel pump or something? Or it's simple gravity feed into the carburetor?
Gas tank has cap and what appears to be fuel filter at the top - black flat plastic piece in rubber grommet, with barb for the fuel line. Fuel line is not pinched. I could not pull that piece out, I tried. Thought, maybe filter got clogged...
Any ideas? Of course, I sold my ZTR last week, confident that I have running mower and, surely enough, here we go.

Thank you.

 

[Kyle_in_Tex]

Make sure gas cap is breathing.

 

[buckeyefarmer]

Yep, loosen gas cap. If it runs, cap vent is plugged.

 

[ukrkoz]

Where's cap vent then? I have no problem cleaning it.
There's no holes in it or else

 

[ukrkoz]

That's what I have.
What to clean? It's super basic.

 

[ukrkoz]

Bump. No one?
Also, anyone knows how to get that black Depurate thing out and what exactly is it? Sounds like filter. I tried to pry it up, even with tools - no go. I don't want to break it as then I am really hosed.

 

[WranglerX]

Should be something like x 1/16 hole someplace in cap.... OR maybe on "DEPURATE" (filter?) where line connects at corner of tank ....

Dale

 

[Kyle_in_Tex]

That's what I have.
What to clean? It's super basic.

Somewhere, under that cap (where you can't see) should be a tiny breather hole. Maybe try cleaning with air pressure pointed from all directions underneath?

 

[ukrkoz]

I'll look again. Surely, I wear glasses, but I'll take my stronger ones with me next.
Any idea how to get that Depurator thing out? Prying on it up, even with screwdriver, didn't really help. And if I break it, I'm dead. As it likely has fuel line attached to it going to the bottom of the tank.

 

[ukrkoz]

Ok, no hole in the cap, positive. the only breathing I can think of is 2 notches in the cap edge on either side of the metal "wall"
Maybe the rubber gasket swell from gas or something, and covers them

Also, here's kicker. I got Depurator out. After prayers and such. Gods were merciful. Apparently, this thing runs on vapor. As Depurator is not fuel filter and does not have fuel line that goes into the tank. It's simple basic vacuum operated valve. Will allow air out, will not allow it back in. Maybe when I over filled tank yesterday, I flooded it and it got stuck?

Cleaned both cap and Depuarotr with spray cleaner. Engine started and ran for some time. I don't want to create much racket, it's 8 am here Sunday.