Replacing check valve on an Echo cs 246

john_ost · April 02, 2021, 09:31:15 AM

I'm fixing up an old Echo cs 346. I've gotten it to the point that it runs, but after 10 seconds or so it shuts off. I believe this means I need a new check valve/fuel vent (though feel free to correct me). I have a replacement valve, but I can't for the life of me figure out where it goes.

Where do I find the check valve?

Thanks in advance

fossil · April 02, 2021, 12:42:50 PM

I did a little reading and one guy said he found it under the flywheel. I can't confirm that but he said he pulled the saw apart and finally found it there.

If you want to confirm it's the tank vent start the saw on it's side and quickly loosen the fuel tank cap and see if it keeps running. If it does, it may be the vent.

10 seconds to create a vacuum in the tank and cause the saw to stall sounds a little quick to me.

If you didn't put a carb kit in it and check the fuel lines for damage or missing parts you may want to do that first as well.
Make sure you didn't reverse the lines at the primer bulb as well.

Guydreads · April 02, 2021, 04:04:58 PM

Also, make sure the carb kit is installed correctly, had that happen to me this week

john_ost · April 03, 2021, 07:37:23 PM

I think you folks are right. It's not the check valve

I just ran it again watching carefully (rather than just recalling what it did in the woods)

I took the bar off and ran it full throttle. It lasted 1:30 before stalling out and smoking profusely. It would not start again. I'll double check that it'll start when it cools down

any thoughts welcome

(the carburator, fuel filter, air filter, fuel pump and spark plug are all new, though there's always the chance I put them in wrong)

thanks

john_ost · April 03, 2021, 08:51:10 PM

Tried it again. This time with the spark arrestor off, and idling instead of revving. died at 1:20, no smoke this time. Just before it died it revved dramatically, even though I was giving it no gas

Tacotodd · April 03, 2021, 10:11:26 PM

Revving up by itself without even touching the throttle is normal. That is a sign of running out of fuel and running lean.

john_ost · April 04, 2021, 04:11:28 PM

@Tacotodd that was it!

I feel dumb

thanks everybody

Tacotodd · April 04, 2021, 10:27:39 PM

@john_ost don't feel dumb, it happens to me also. For instance, I thought that was going to be tearing into my oiler on my lil Echo CS550P. All that happened, I RAN OUT OF OIL! THAT made me feel downright stupid, but I'm SURE glad that it was a SUPER easy fix. Fill with oil & away I go!