Small Engines (Lawn Mowers, etc.): Craftsman Trimmer 358.795190, audible indication, plug hole

Question
Hi Eric,

For quite awhile my trimmer would only start if I sprayed (I think it's) small engine cleaner into the spark plug hole.  When started, it felt as though I needed to keep the trigger pulled (keeping it out of idle) to keep it from dying.  At some points during this time frame I've opened and closed (slightly) the idle screw.
Just recently I finally inspected the trimmer and noticed that a fuel line was cracked at the end and the others were shot as well.

I replaced the 3 lines, replaced the air filter, replaced the fuel filter and reset the idle screw according to the manual.  It started fine and seemed a touch better but eventually died on its own.  After that I replaced the spark plug with some sort of super spark plug.

I tried to start it up.  The first pull in full choke sounded normal.  After that, the other pulls at full and half choke did not give any audible indication of wanting to start.

I'm not sure what else needs to be done at this point.  I did notice that when you take the spark plug out, you'll see black gunk inside that area of the engine or crank. The fuel that I use is only about a month old.

Any ideas, please?

Thanks,
Shawn

Craftsman Trimmer 358.795190

Answer
If the fuel lines were cracked odds are the carburetor parts, made of a similar material, are also hard/brittle and not working correct.


The parts list says you have a WT carburetor.  Service manual link below:

http://wem.walbro.com/distributors/servicemanuals/WTseries.pdf

I'd start by rebuilding the carb following the directions in the service manual.  DO NOT remove welch plugs...just replace the diaphrams/gaskets and clean the carburetor with compressed air from an air compressor.  Be sure to check the meter arm lever height.

Also, the o-ring on the main housing is prone to leaking.  Remove the rear engine plastic, clean the o-ring/housing with brake cleaner and then apply permatex #2 non-harding around the o-ring and re-assemble.

Let me know if this helps.
Eric