Hi all...

Some of you may recall I needed help in diagnosing my parents' Toro
mower engine.
The thing would start, run about one or two seconds and then die. I
checked the plug, even tried several new ones, gas float and so on...
Well, this weekend I took the carb apart to clean it up. I didn't find
anything out of the ordnary. The passages appeared clear and the main
tube running from the gas bowl into the throttle body was clear as
well.

I put the carb together, installed it in the engine and found the same
effect. Prime the engine about 5 times, start the motor, motor would
run for 1-2 seconds and die, it would not start again unless I primed
it.

I measured the cylinder compression to be about 90 PSI.

Then I tried to choke the air intake by removing the air filter and
jamming a piece of cloth to restrict the air intake.
I started the motor. It ran very rough, so I slowly withdrew the cloth
from the air intake. Had I pulled it out right away, the motor would
die once again.
After about 10-15 seconds, I was able to completely withdraw the air
obstruction and the motor ran fine. Once warmed up, I could stop it
and restart it without a problem.... but once cooled, I would have to
go through the exact same routine of introducing a "manual choking
system".

Hence the question.... do these motors have some sort of a choke, or
am I missing something? Is there something obvious that could be
causing my problem?

thanks
Alex