Echo CS-501sx ignition

[lux]

Unusual for NGK to break. The tight ring groove - use the broken ring to make sure the new ring fit isn't tight otherwise the ring will wear badly and not seal well.
It is tight as the broken electrode will have impacted the edge of the piston crown - there should be a visible impression of the electrode on the piston crown edge and probably the squish band on the combustion chamber.

No notable mark but there was a tiny ridge on the piston crown on the exhaust side edge. Quick rub with super fine wet and dry it was gone.
If that top piston ring grove is slightly compressed I’m guessing new piston required.

[spudulike]

You can usually work the old ring in and out, scrape a little of the bruised metal out until the ring slides in and out freely.

[lux]

You can usually work the old ring in and out, scrape a little of the bruised metal out until the ring slides in and out freely.

Cheers spud [emoji106]

[peatff]

Has the original poster tried disconnecting the kill switch wire ?

[BobbyDee]

16 hours ago, spudulike said:

No way of testing the coil as it contains a lot of electronics rather than just a conventional electronic coil.

The usual method is to test the HT lead from the cap to the laminate earth and you should get some sort of reading this way. The next thing is to set the gap much smaller than normal by using printer paper, disconnect the kill wire and see if you get a spark - I open the end electrode up to a 45 degree angle so you really get a good spark as it is easy to think the coil or plug has failed because you aren't generating a big fat spark. Also - give the engine a BIG pull when testing, some need to be spun over fast to generate a nice spark.

If you still don't get a spark, it is very likely that the coil is shot - I did have a flywheel lose its magnetism once but it is rare and rarer still on a modern machine - it is usually heavy impact or age that messes them up!

Just what I needed thanks. I am currently turning the engine with the pull mech removed and using an 18v cordless drill and socket. Fuel is coming through fine but there is definitely no spark. Turns out that the reason I couldn't source a replacement coil is because Echo has changed the part number to P021 037431 and it's around £100 all-in which is somewhat less than a new saw.

[BobbyDee]

2 hours ago, peatff said:

Has the original poster tried disconnecting the kill switch wire ?

Nope - never thought of that. I'll try it. Thank you.

[spudulike]

4 hours ago, BobbyDee said:

Nope - never thought of that. I'll try it. Thank you.

It was on my list but hey ho......

[BobbyDee]

29 minutes ago, spudulike said:

It was on my list but hey ho......

Missed it Spud and went straight for the continuity test but I've also now tried the kill switch and it ain't that either so I've ordered a new coil. I shall update here as soon as I can. Thanks again.

[BobbyDee]

I ordered a replacement ignition coil for the CS-501 2 weeks ago. I've now been informed it will be 'at least' another 2 weeks before it arrives.

Not a great advert for Echo.

[coppice cutter]

3 hours ago, BobbyDee said:

I ordered a replacement ignition coil for the CS-501 2 weeks ago. I've now been informed it will be 'at least' another 2 weeks before it arrives.

Not a great advert for Echo.

I believe the importership has changed hands relatively recently.

 

Maybe that's a factor, on top of Asian supply chain problems which are still ongoing.