[Shop-talk] Echo string trimmer

[Pat Horne]

Thanks for all the replies. Most of them didn't go to the list though.

I've received replies ranging from "Yup, sounds like ignition" to 
"definitely Carb". The first thing I am going to check was simply "reed 
valve" I forgot all about the reed valve on 2 strike engines!

It will probably be Monday before I will be able to get to the engine 
again, a swarm of bees decided to set up house inside my shop this 
afternoon! Hopefully they are just the night, then then move out in the 
morning, but I somehow doubt it. There was a swarm in one of our Oak 
trees a couple days ago, so they are looking for a place to call home. 
It is pretty disconcerting to have several thousand bees flying around 
you when you are trying to work.

Peace,
Pat

Thusly spake David Scheidt, On 6/11/2010 1:49 PM:
> On Fri, Jun 11, 2010 at 1:43 PM, Pat Horne <pat at hornesystemstx.com> wrote:
>   
>> A few days ago I was cleaning out a fence line. The string trimmer was doing
>> fine. Then it was as if someone just turned off the switch, it slowed from
>> full speed to stop without any poor running or noise.
>>
>> The fuel is fresh, with the correct mixture.
>>
>> I gave it a shot of ether to see if it would start, it did not respond. To
>> me, this rules out a fuel problem.
>>
>> I replaced the plug, which looked good.
>>
>> After a trip to the local lawn equipment shop I was told that compression
>> was low, and that I should just buy a new trimmer. They also said that I had
>> a 4 cylinder spark plug in it, and that they run hotter than the 2 cycle
>> plug, possibly burning the piston.
>>
>> I didn't think that the compression was any lower than it has been for
>> years, so I brought it home and pulled the cylinder. The piston looks fine
>> and the rings are not stuck. There is no scoring of the cylinder or piston.
>>
>> I connected a neon electrical test light from the high tension lead to
>> ground and got a spark. Connecting the light in series with the plug and
>> lead did not produce any light. I figured that the coil went bad. I have a
>> spare engine from a Mantis tiller that is made by the same company as the
>> Echo, so I mounted up the coil from that engine but got the same results.
>>
>> The shop said that in their 30 years of being in business they have never
>> seen an ignition coil or flywheel on these engines go bad.
>>
>> My money is on the ignition. Anyone else have any guesses?
>>     
>
> Do you have an inductive spark tester?  (A timing light will work, if
> you hook it up to another 12v source) Is the HT lead part of the coil,
> or a seperate part?  I'd bet on that.  But yeah, that smells like an
> ignition failure.  I've seen the magnets break off the fly wheel.
> There's also a capacitor in most magnetos.
>
> I suspect the reason they've never seen one fail is because people say
> "hum.  80 dollar tool.  100 dollar shop bill."
>
>   

-- 
Pat Horne, Owner, Horne Systems 
(512) 797-7501 Voice		5026 FM 2001
Pat at HorneSystemsTx.com	Lockhart, TX 78644-4443
www.hornesystemstx.com
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