Echo Weed Eaters Not Starting

[StarTech]

Would not hurt to do a compression test. If it is below 100 psi with the throttle held open then the PNC is worn out. Flooding with a known good carburetor is usually a sign of weak compression, clogged spark arrester, or ignition problems. But even a stiff metering diaphragm can cause flooding.

 

[Hammermechanicman]

The only time i have seen incorrect spark timing on a string trimmer is when someone put the wrong coil on or a cheap aftermarket one. If the trimmer has the original coil i doubt it has incorrect timing. That leaves fuel and compression. Pulling the muffler and a flashlight to look at the piston and cylinder would go a long way in checking compression along with checking all crankcase screws. A can of starting fluid will solve the fuel question.

 

[StarTech]

For me I have seen it happen with non clutched models where the flywheel key gets sheared.

But when you have the non invasive test tools, you save time by checking things using them. This why I use the compression tester and pressure/vac tester. Usually if the compression is low I do pull the muffler and check the PNC to confirm damage. If damaged I call it and return the unit to the customer as not feasible to repair.

When I first started working on two cycles I did a lot unnecessary disassembly work but now I can usually tell the causes with 15 minutes using the test tools. Sometimes it takes longer to get the tools out then actual troubleshooting.

Even the Echo trimmers here that uses plated cylinders, the plating will wear through easily especially under commercial use. The SRM-225 here at the Nursery customer usually only make it two years before being worn out where a Stihl lasts much longer.

 

[slomo]

I would pull the mufflers and clean all the carbon out of the entire exhaust side of the engine. Clean is clean is clean is to clean.

Remove the window screen, EPA, US Forestry spark arrester and throw it in the trash. Unless you are trimming in a forest that is. Not really needed for a home owner.

Most likely you have a carb issue.

 

[Hammermechanicman]

The average joe probably doesn't have a spark tester, compression tester or a pressure and vac tester. I was trying to give the OP some things to diagnose and not guess without special tools. I have seen more than one 2 stroke with good compression but had scoring and wouldn't run properly or not at all

 

[JMK1038]

Timing
The flywheel should have a key cast in it
These can shear & put the timing off
Put some lines on the flywheel with a paint pen against some sort of marker corresponding to TDC & 1/4 either side of it
Ground the spark plug & hook a timing light up to the spark plug wire
This way the units will rotate easy
use a drill to spin the flywheel in the right direction and see where the flywheel ( thus piston ) is when the light flashes .

check compression. below 80 bad.100 and above great. 80 to 100 might start if closer to 100.