Need to get this saw fixed.

[cbfarmall]

I'm working a cheapie Echo for a friend, CS-5000. Can't get it to run because it'll flood after a couple of pulls. Diaphragms were stiff and dry so I replaced them. Cleaned the passages, inlet needle seemed to seat fine. Saw still floods. Only way to get it to fire is to close the adjustment needles.

Somebody worked on this thing before me--one of the screws in the metering cover is different and the air cleaner boot was incorrectly installed letting dust get into the carb throat. Had to clean a bunch of dirt off the butterflies.

Thanks, Chris B.

 

[cbfarmall]

I went outside and took the carb apart. Cleaned again as good as I could as I could. I reconnected the fuel line and what do I notice....fuel is trickling out of the main nozzle in the carb throat--without the engine running. The gas tank evidently creates some back pressure from evaporation and expansion, but shouldn't the needle stop this trickling?

 

[glens]

Check that the needle, seat, spring, and lever are all in good working condition.  Also check the lever height.  It's typically supposed to be flush with the top of the machined surface for the diaphragm/cover.  Also, if the spring has been tweaked in any way it may not now be the proper tension/rate.

Glen

 

[cbfarmall]

The lever height is set with the needle and pivot fully set into the closed position, correct? The diagram with the diaphragm wasn't specific on this point.

 

[John in MA]

Right, closed is the default position if you have the spring in there.

My XL-98A demo saw has this problem. I determined it to be the elusive brass check valve, although I still haven't found anyone who can give the part number so I can order it.

 

[jokers]

Hey Chris, are you sure the metering diaphragm isn`t in upside down, it can cause a problem like this. Like Glen said, also check meter lever height.

Russ

 

[cbfarmall]

I put it together the way I took it apart, but I guess I can't assume the guy before me fixed it right--wouldn't be the first messed up item I've found.

Diaphragm goes against the carb body with the metal disk facing in, then the gasket, right? (I think it'll go together only one way.) I've checked the lever height and it is dead on.

In any case, I've got a carb kit on order so I'll install that and go from there.

Thanks, Chris B.

 

[glens]

First try swapping the gasket and diaphragm.  There's no need for a gasket on the atmospheric side and if it's missing from the vacuum side it would be the equivalent of the lever being set too high by the thickness of the gasket.  The result of that could be the needle not fully seating.

Have a look at http://www.aerocorsair.com/id27_m.htm for a good general overview of a couple of carb styles and with excellent images and photos.

Glen

 

[cbfarmall]

Looks like I found a problem. The gasket and diaphragm are backwards. I'll fix that first thing and see what happens.

Thanks, Chris B.

 

[jokers]

Hi Chris, the problem you found is what I was trying to point out but didn`t. I reread my reply this morning and thought to myself "that reply makes it look like I was drinking", LOL. Luckily you and Glen were all over the right answer.

Russ

 

[JimL]

Originally posted by John in MA
Right, closed is the default position if you have the spring in there.

My XL-98A demo saw has this problem. I determined it to be the elusive brass check valve, although I still haven't found anyone who can give the part number so I can order it.

seen that before, guy came in and asked how I cleaned the carbs, I told him i take a realllllly small wire and run it in all the little holes and flush it and do it again and flush it.

He brought the carb back and said he did that and this one brass "jet" he called it had a chunk of rubber or something in the way. oops.

 

[John in MA]

How the heck can I get a new one, anyway? I know they sell them separate from the carb body. Even Tillotson's online parts breakdown doesn't show it, although the troubleshooting chart says to replace it for one problem or another.

 

[stihltech]

carb jet

What model carb is it?

 

[cbfarmall]

Update to fixing the Echo Saw

I found the problem with the Echo carb. Seems the guy who worked on it before me lost one of the screws for the metering diaphragm cover plate. He decided to replace it with the screw that held down the metering lever pin. As a result, the lever wold just flop around in the carb flooding the engine. Put the screw back, and swiped a cover screw off a junk carb and it runs like a champ now, relatively speaking.

Now I've got to send the carb kit back.

Thanks for your help, Chris B.