How old is this mower -- does it have ignition points or modern transistor
ignition. It sounds exactly like my 30 year old Troy-bilt tiller. If I
didn't engage the tiller tines carefully it would stall or would only slowly
build up revs. The points were dirty and needed replacing. Followed my
manual exactly in regard to installing the points and how to re-time the
engine while replacing the points which required removing the head. While it
was open, I scraped carbon off the piston and the inside of the head. Put it
all back together and fired it up. The old engine fired up immediately and
had its old power back like a new engine. This was a 30 year old Tecumseh.

"Daryl Helwig" wrote in message
om...
Husky rider w/20hp Kohler Magnum (1995ish). Spec #57528.

For a long time it ran rough. Surges a lot. Throttles up slowly. Blows
black smoke when throttling up. I'm told this is carb problem.

The other day I'm mowing and its running rough and surging. When the
rpm's are on the way up it blows black smoke. But after a while it
starts to stall out. I shut off mowers and it gradually gains rpm's.
Mowers on...dies. Mowers off...slow recovery. I drove back to the
house and it died. Wouldn't restart.

Checked spark. None sometimes or very weak. Found that the spark plug
wire connector is rusted and starting to crumble. Ah hah! Could the
slow deterioration of the connection cause a bad spark which caused
the rough running and black smoking? Soooo, I replaced spark plug
ends. It started up. Ran rough. Sooo, I took the carb off and tore it
apart and soaked it in cleaner. Reassembled. Started immediatelly.
Still gains rpm's slowly. Turned mowers on. Engine immediately dies
just like if the key is turned off. Turn the mowers off and engine
gains back it rpm's.

Any ideas? I'm stumped.