Echo cs 600p help!

[Zach Powell SER]

Hello experts! Brand new to this site. I’m a small engine tech and I’m working on an echo cs 600p.
The owner said while operating it that the rpm’s began to race and it wouldn’t shut off. After getting it to stop he restarted it and it would idle but cut out after the throttle was applied. I took apart the carb and cleaned it. I put it back on and started it. I can get it to run good with the low speed adjustment screw backed out about 3 1/2-4 turns and the high speed at about 3/4 of a turn. With the idle set about 3/4 in. It’ll start and idle and spool up, but when I let off the throttle it dies and won’t return to idle. I’m wondering if it’s the diaphragms since he said he uses ethanol fuel. Any help is greatly appreciated.

 

[Marley5]

I'm betting diaphragms.

Tell that guy to quit using ethanol fuel, it also leans the saw out and makes it run hotter but I'm not arguing with people that says it's harmless.

I know a thing or two cause I seen a thing or two. Lol

 

[nixon]

Initial set up on the carb is : La screw 2 3/8 turns in , low side needle 2 turns out ,high side needle 3/4 turn out .
Not much help , I know . But once you sort out the carb , that’ll give you a decent point to set up the saw .

 

[Leonard Meehan]

Hi Zach. Repairing can be fun but diagnosis not so much. If it were me I would hit the reset button on the procedure. Treat the saw as if you just got it and are doing an inspection. Check what you would normally do. I would probably pull the muffler and look inside. Does it have good compression. Dump the fuel and look for dirt. If it all looks good and I had another carburetor I could test with a carb that i know is good. I would try to isolate the problem to the carb or something else. Take a look at the spark plug maybe it can tell you something. The low screw out 3 ½ turns can indicate a restriction in the fuel delivery or an air leak. I have also seen this with a scored piston. E fuel can run hot and the run away the owner mentioned gives me some concern. Maybe the echo tech guys here can give more I am just a hobby chainsaw guy but have been a mechanic for over 50 years. It will feel good when you figure it out so good luck.

 

[drf255]

Could be a vacuum leak. I’d do a vac and pressure test first and check piston while you are at it.

 

[Cliff R]

Running E-10 will not hurt the saw in any way. It takes about 5-7 percent more of it to do the same thing as non-Ethanol fuel, so custom tuning is required if you want to make best power and avoid running a bit lean.

I've been running my CS-590 and 600P on 92 or 93 octane E-10 for many years with zero issues. I've logged about a zillion hours on the CS-590 and aside from wearing out a couple of bars and several dozen chains it's flawless. I used it a couple of months ago to cross-cut a HUGE Beech tree to make the 12-14" wide pieces manageable to the splitter. It never crumbled once and you've got to love those saws for "noodling" as they don't even think about plugging up like most of the other bigger saws in my line-up........Cliff