Echo String trimmer carb

[lefty]

GT-200R
S72612307905

This is the continuation of the story of my life. I've had terrible luck with rebuilding 2 stroke diaphragm carbs. This is a personal machine of mine. It had a problem with bad fuel lines and a hole in the purge bulb. I decided to do a carb kit on it and replace the fuel lines /assembly. I also replaced the purge bulb. I completely disassembled the carb and ran it through my ultrasonic cleaner for about 20 minutes with a solution of water and dawn dish soap. I decided to clean it like this because there was a good amount of debris in the chamber. I blew it out with very light air pressure just to dry off the outside and let it sit over night before reassembly. The diaphragms were hard and I replaced those, gaskets, needle and lever and screen. verified proper adjustment of the lever.

I assembled everything. It won't purge. Nothing happens when I press the bulb. I can't get fuel to move through the system. The bulb has the proper feel when pressing it's just that nothing is flowing. I don't want to give up on this one. At least to say I was successful at least once.

Does anything jump out that would be responsible for this issue? No action with the purge bulb? I'm not hearing air move or anything. Dry as a bone. I always assume that I ruined a check valve somewhere by running through my cleaner but I was super gentle with it this time. It functioned before I got involved with it so I can't imagine it's not my fault.

Thanks.

[KE4AVB]

Most likely it is a stuck check valve. Until this year I haven't had any primer to give problem and now I had three in a row to have failed.

[lefty]

Where is that check valve? Is it in the plastic block between the bulb and the body of the carb?

And did I screw it up when I washed it?

[bgsengine]

I'd start by seeing if you can get fuel to actually flow through the carburetor. (Remove metering needle for the test) hook carb to fuel tank with some fuel in it and the cap on, then take a length of tubing and hold it to the return line and blow some air into the tank and see if fuel flows through freely. If it does then put your metering lever back in and re-test. if not then you maybe got gaskets in wrong order. If you had the vacuum/pressure tester set (Its mentioned in several places in the forum) then there's a bunch of tests you can do with that to diagnose the entire fuel system in 10 minutes or less and have a pretty solid 99% chance of knowing exactly what's wrong. (If your fuel line has a pinhole for example outside of the tank, then your purge is just gonna be sucking air anyhow!)

[lefty]

I do have a mighty vac. I'll give that a go in the morning. Thank you.

[KE4AVB]

These are the location of the two small under 2mm flat rubber discs with springs holding the checked position. Cleaners tend cause them to stick which why soap and water only should be used to clean these carburetors. So spray carb cleaners are a no no.

And if you wire probe these you can damage them too.

[lefty]

Thank you. I did not use any solvents, just soap and water. What are the chances that it is salvageable? Do they sometimes stick or is it a thing where once they're not working, you're done?

[KE4AVB]

It is one of those may and may not things. Just not enough experience to say one way or the other as I have had both. A few I was able to free up and others I haven't been able. Sometime when I get one free up it just sticks again.

[lefty]

Thanks. I just had the same experience. I freed it up but not adequately. Couldn't get it to run right. I replaced it with a new aftermarket one. Thanks again.