Small Engines (Lawn Mowers, etc.): Snapper string trimmer, crankcase pressure, compression gauge

Question
Have a Snapper string trimmer, S31 SNGBC.
Hard to start. Replaced gas, plug, still no go. Suggestions?

Answer
How old is the trimmer?  Have you checked the muffler to make sure the ports are clean?  Is there any oil build-up on the lower engine housing?  Sometimes the gaskets leak and will cause hard starting due to loss of crankcase pressure.  Often times applying RTV or Permatex #2 non-harding sealer on the gaskets and re-assembling will solve hard starting on Weed Eater brand units.

Did you check the compression?  You need at least 125 psi measured with a compression gauge for the unit to perform correctly.

While I love Snapper 21 inch self-propel mowers, the best on the market in my opinion, their string trimmer line is not near as good as their mowers.  In fact, Snapper contracts with other manufactures to build string trimmers for them.  Another manufacture will modify the plastic resin for the cases to meet Snapper brand red and then make Snapper stickers to put on the trimmer.  Your trimmer is actually manufactured by Poulan/Weed Eater.

If the trimmer is over 5 years old you may be better off purchasing a new Stihl.  The FS45 cost $140 and is rated very high by Consumer reports.  The FS55 runs a better than the FS45 but of course it costs a little more.  The FS90 is awesome but will cost around $200 and up depending on what accessories you get.

Bottom line, if your Snapper trimmer has low compression it is not worth fixing.

Let me know if this helps.
Eric