On Fri, 25 Jun 2010 12:37:59 -0700 (PDT), OTP
wrote:

On May 1, 2:28*pm, "W. eWatson" wrote:
I've had Subject trimmer for ten years, and of late it has been hard to
start. I've probably yanked on the cord about 80 times this morning, and
a few times it sputters and dies. I've had it in choke and run
positions. Usually run gets it going. The outside temp is 62F. The
little transparent fuel clear bulb has lots of fuel in it, as required.
There is a bubble in it that may be 1/2" in diameter. I used it the
other day for 30 minutes.

How to proceed?

I have owned my FS36 for almost 15 years. Had it tuned up 4 years
ago. Recently it started to lose power, then last week it just
wouldn't start. I went to local Stihl sales/repair shop with it. They
quoted $90 to fix it, or $149 for a new FS49. I retreated to think it
over. Today, after reading the book carefully, I repaired it and it
runs like new. I cleaned the spark plug, and air cleaner but the item
that isn't mentioned in this thread is the Spark Arrester. I cleaned
that and I believe it was that which made the difference. It was caked
solid black. I removed it, put in in my vice, (clamping it along the
margin of the little screen) and started scrubbing it with a fine
guage wire brush. I kept kept flipping it around and scrubbing and
soon it was as good as new. Put it in, and the engine started up with
one pull! I trimmed all day and it performed like a champ. The
owners manual clearly states that if power starts to fail, to replace
the spark arrester. That is an easy to miss or dismiss
recommendation. Total out of pocket expense = $zero. PS. If you
want to take the rear plastic body cover off to tidy up or just
explore the engine's layout, you will need a 9/64 long-tailed Allen
Wrench.

You make a very good point. Carbon deposits in a spark arrestor or a
carbon clogged muffler are not normally mentioned here, regarding it
being a possible problem.

Thanks.