Harry wrote:

I have a Honda Harmony 1011 Mower - it is a very nice 30 inch riding
mower with rear bagger.

It starts up first time - every time - if I give it a squirt of starting
fluid. Then it runs forever. If you restart it hot - it starts fine
without the starter fluid. But when it is cold or has not been started
in an hour - you must squirt some starting fluid into the carb.

It just started doing this - before it started fine every time - hot or
cold.

I have changed the oil. I have cleaned the air cleaner. I removed the
spark plug - it is clean and dry.

I repeat - it starts first crank every time - with a shot of starter
fluid into the carb.

I would hope so...

Any ideas on a fix?

Sounds like weak spark/old plug or dirty carb or choke not fully
closing. Does this have a "prime" bulb or fuel pump or is it gravity
fed?

The problem is the mixture isn't right or the spark isn't hot enough so
that it isn't firing off when cold. Fix whatever is weak/out of
adjustment there and it'll start.

Of course, depending on how old it is, it could be somewhat more serious
but if the plug isn't showing signs of fouling, it probably just needs
good tuning/tlc...