Echo CS-300 Problems

tim1234 · July 13, 2007, 10:30:15 PM

I've been using my little CS-300 for about 5 years. Has run great, started with no problem and never stalled unless it was out of gas. Out of the blue last Saturday, about half way through cutting some small trees the saw started idling fast (chain moving at idle). Then it started idling rough and started stalling.

This is what i have done so far.

1st thought was a clogged fuel filter. Got a new one today, didn't help.

2nd thought was bad gas. bought some new midgrade, mixed er up, emptied the saw, ran it dry and filled with the good suff. Didn't help.

Hmmm.....maybe it's the air filter. Cleaned it off almost as good as new.....why not give the saw a good cleaning as well. Didn't help.

nuts...well, maybe its the plug. Pulled the plug. It's pretty good but the gap is pretty large. Bought a new plug...didn't help.

One of the guys at work mentioned a clogged spark arrester screen could cause some running issues. Removed it, brushed it clean....didn't help.

Did the engine give up, like a piston ring, or could it be the bad gas lacqured up the fuel system? The gas was about 2 months old, but the oil has stablizer in it.

Any suggestions?

I really love this saw...if it is really dead, what are the husky or Stihl equivalents. I take the saw climbing with me when I'm trimming so I really like the small light CS-300. I don't think Echo makes it anymore.

Tim

ladylake · July 14, 2007, 06:14:38 AM

First check fuel and impulse lines for cracks, if none then take the carb apart and give give it a good cleaning, check the diaphram that pumps the fuel for cracks or tears. Also check the rubber boot between the carb and cylinder for tears, if you got the saw pinched and were yanking on it hard that can rip that rubber boot. If none of the above it could be the crankcase seals leaking air.. Befor you start any of the above make sure the carb mounting screws were tight. The cheap home owner Stihl and Husky saws are not as good quality as Echo's. Also try and run gas with no ethonal in it, doesn't go bad as fast. Steve

tim1234 · July 14, 2007, 10:50:20 AM

Thanks Steve,

I did get the saw stuck. I was trying to cut down a small snag that was bent and cut too deep on the compression side. Had to cut the saw out with my hand saw.

You mentioned a rubber boot between the carb and cylander possibly being torn. How does yanking on the saw tear something that seems to be part of the engine? Does it create some reverse compression? I really don't know my small engines very well, but nothing like a "life lesson" to learn fast!!!

Tim

tim1234 · July 14, 2007, 10:59:52 AM

One other bit o info. The saw does run ok at full throttle. It seems to be running a little hotter now. The saw just runs rough at idle and then stalls. Still start fine.

Will check that boot in a few minutes.

Tim

ladylake · July 14, 2007, 08:13:48 PM

Tim The carb is mounted to the handle bar housing which has rubber mounts between it and the engine, when you tugging on the handle bars the rubber mounts flex along with the rubber boot which is between the cylinder and the carb. Sound most likely it tore, don't be running the saw untill it's fixed. It will be running lean on high speed and could burn up. Steve

tim1234 · July 15, 2007, 09:12:41 AM

Steve,

I opened up the saw yesterday and decided and after I took a look inside I decided to go in a download the manual and parts caltalog. At least that way I could look at how everything fit together before I start tearing it apart to inspect everything.

I've started to take a digital picture of stuff before I take anything apart so I can see how everything fits back together if I get stuck. I'll take it apart this afternoon so I can order any parts tomorrow.

I found 1 place online that seems to stock all the parts.

Thanks for the help.

Tim

ladylake · July 15, 2007, 01:18:52 PM

Tim Good idea to take pictures, once you get it apart it's not that bad. Getting the carb boot in can be tricky on some saws. If you can find a Echo dealer close by I'd get the parts there, same price and save on shipping and would give you advice on the best way to gets the parts in. Steve

tim1234 · July 15, 2007, 06:30:37 PM

May take a little longer to get to that saw repair. My 2 year old thought it would be a good idea to stand up in the seat of the shopping cart just as my wife started moving the cart. Fell right on her head, so we made a trip to the ER today. She's fine, charming all the doctors.

Tim

tim1234 · July 15, 2007, 08:28:52 PM

Steve,

I got started on the teardown. I didn't find any damage. Here are some pics of my Carb Repair 101. Of course I'm the student!.

Here's a pic of the saw.

Here is a pic of the whole assembly after the air filter is removed.

The carb came out once I removed the 2 screws on the top and disconnected the throttle, Purge Pump hose and fuel line. The carb was clean as a whistle. Almost looked brand new.

Below the carb was the valve assembly. Pretty simple spring with a stop on the inside. I can see a little bit of oil and sawdust on the inside of the valve. I assume the boot you were talking about is the gasket that is between the valve assembly and the saw case. It looks like this keeps the dirty air from entering the carb chamber from the back side. It looks like it might have shifted letting a little sawdust in.

Steve is this what you were talking about?

There wasn't any damage, although I don't know if I can get the gasket back in place since it is not very hard and does not retain it's shape well. I'm afraid if I reassemble without getting a new one it will leak again.

Here is the case and block with the vavle assembly removed. I was real supprised to see the sawdust below the assembly. I guess the seal you are worried about here is between the valve assembly and the block. Is this pretty normal or is there something wrong here?

You were right, it came appart pretty easy. Hope it goes back together just as easy.

Do you see any problems? There is nothing torn. Like I mentioned previously, the gasket did look like it shifted a little letting in some dirt. That's the closest thing I saw to a boot.

Tim

ladylake · July 15, 2007, 11:01:29 PM

Tim It looks like you have a reed valve saw, the rubber boot would be where the reed valve is. I've never worked on one yet. If you think that gasket was letting in sawdust it would sure let air in causing your troubles. Maybe get new gaskets and clean everything up, put it back toeghter and see how it works. I've heard on the small engine forum that a little bit of sawdust getting in the reed valve will make it run bad. Also check the fuel lines real good for cracks, they look good in the pictures but you need to bend them around a little to tell for sure. Nice piuctures.. Steve

tim1234 · July 15, 2007, 11:27:39 PM

New digital camera from my wife for christmas last year. My wife uses it as a scanner for docs it's so good.

All the fuel lines are perfect. Still very flexible and no cracks.

Looks like I need to find a local parts store or hit the web!!

Tim

tim1234 · July 19, 2007, 06:34:13 PM

Parts are due Monday, but they are presently in transit from Ohio to Mi so I am hoping the come tomorrow. I've got an itch to go cut something after the day I've had.

Tim

ladylake · July 20, 2007, 07:17:01 AM

Tim Hope you get it running good again. I have 7 Echo's along with 3 Stihls a Husky a Solo a Cub Cadet and a Dolmar. My Echo CS6700 and CS510 are the one's that come with me to the woods the most, they're light, handle nice and gutsy. The only one that I don't like real good is the CS8000, It just doesn't seem to have the snort it should. Steve

tim1234 · July 21, 2007, 01:33:19 PM

Got impatient today so I decided to tinker. I put everything back together after a thourough cleaning and wadayaknow.

It runs like a champ. Well at least I have the spare parts just in case. Now the saw will never break down because I already have the parts ;D

Tim