Echo CS 8000 Backfires Through Carb

[Old2stroke]

For whatever it may be worth -- and you can say it's not much (and that doesn't bother me) -- I have had the problem of spark timing at start (including 'kickback' etc.) when the plug has shown spark and the flywheel key is fine, and I have had the problem of very weak to no spark in compressed conditions at slow rpm when the plug has shown spark (admittedly a little funky-looking, not the sharp little blue snap). Agreed most of the coils that fail just completely fail - no spark at all, a winding opens, or a semiconductor eats it - but I don't think those are 100% of the ignition failures.

You have pointed out another common failure mode, no spark at low rpm. Every ignition system has a minimum rpm that must be achieved before a spark will occur and when electronic components change this minimum rpm can drift up and you can end up with no spark at normal cranking speed.

 

[Lil'Skeet]

This one gets style points......how does anyone hold a timing light, in 1 hand, and a drillmotor in the other? Priceless humour.

Chain bar in a vice, sparkplug out and grounded (get creative to hold it down) to visually see spark, leaves (2) free hands for timing light and drill.

 

[Lil'Skeet]

You have pointed out another common failure mode, no spark at low rpm. Every ignition system has a minimum rpm that must be achieved before a spark will occur and when electronic components change this minimum rpm can drift up and you can end up with no spark at normal cranking speed.

Usually what I have found to happen when a coil starts to take a sh#t. Low rpm and cold temps and they don't act right.

 

[rmh3481]

There were two different coils and two different flywheels used on the 8000. They dont mix and match. The early system uses 3 magnets on one side of the flywheel. The later system uses 2. The early coil has a JEL stamp and the later is Oppama. Another indicator on the later coil is the letter 'A' over near the hold down bolt. Early coil is not marked.

If a late model coil is bolted down with one of the earlier flywheels the spark timing is around 50 degrees out of time. You will get a back fire but that is all.

Identify which flywheel you have and go from there.

Echo sells a kit which has a new flywheel rotor and a new ignition coil for $100 under part number 15600230831. If you want to go thru ebay, I see Duke selling the kits. If you have questions shoot me a message.