can anyone tell me why my new echo cs-490 is very rich until i make a couple cuts with it then it leans itself out the spark plug is grey and white no matter how far i turn the high jet out, ive pressure tested it and it holds 15psi even when i pull it over, it has a muffler mod done, gas is mixed at 50:1 i thought it had an air leak but it holds pressure and vacuum both at 15psi with the muffler and intake blocked off between the carb and intake boot. any help would be greatly appreciated
Echo CS-490
- Thread starter don5477
- Start date
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If new take it back to the dealer to have it serviced. You could have a partially clogged high jet? You certainly don't want to use one lean ESPECIALLY when breaking it in. Stop using it now until the lean condition is addressed or you could burn a piston. Is your fuel fresh, clean and mixed right? Pour out what fuel is in the saw and fill with 40:1 premix. If new take it back to the dealer to have it serviced.
i bought it from a seller on ebay it said new open box but it was cheap, fuel is mixed good and is fresh at 50:1 i have other chainsaws so i won't use this one until its fixed i wonder if there could be something bad in the carb. thanks for the reply
Ask the ehay seller for the original sales slip. This saw is guaranteed for 5 years if not modified. Have you verified that the piston is in good shape and not already burned? If your seller will not cooperate and the saw is not warranted you could still take it to a qualified Echo dealer and pay to have the problem taken care of if it is as simple fuel flow problem. Are the adjustment caps still on the carb? I have a cs490 and it has been and continues to be problem free after several years.
There are members in this community who have tons more mechanical knowledge if they are willing to chime in. Give it a little time and see if someone else on the forum will help. Post back with detailed info such as how /why do you think it rich at start up and any other detailed information.
There are members in this community who have tons more mechanical knowledge if they are willing to chime in. Give it a little time and see if someone else on the forum will help. Post back with detailed info such as how /why do you think it rich at start up and any other detailed information.
the seller will be no help, there is no marks on piston or cylinder i had the exhaust off to look inside, i don't think it was ever ran before i got it, i also took the caps off the carb to adjust for muffler mod when i start it for the first time after cooling down it pores blue smoke out the exhaust but clears after i make a cut or 2, then after the cut or 2 it gets very lean to the the point that its white on the spark plug, my fast tach says 11500 for max rpm then goes to 12005 after i make a cut or 2, if i let it set and cool then its back to 11500 again
After warm up can you open the high speed adjustment far enough to make it four-stroke out of the cut? Explain your muffler mod in more detail please. Check for collapsed fuel lines and clogged filters. Then unless others chime in I don't know what else to suggest other than carb replacement.
Huskitoter
ArboristSite Operative
Check the fuel tank vent by turning saw on the side and open the fuel cap when it starts to run lean. Longshot but easy to check.
i will try that tomorrow if that works ill post. thank you
Maybe post if it works or not.
tank vent was good so i took the carb off today and took it all apart cleaned it real good with carb and choke cleaner and compressed air i didn't see anything but there must of been something in there because it is running the way it should now. thank you guys for all your help on this
Good to hear. The carb issue may be the reason that your saw was for sale cheap. Keep the 490. I think you will like it. Be careful with using carb and choke cleaner. It can destroy carb parts such as diaphragms, gaskets, o-rings and such. Sounds like you got it clear with the compressed air before doing any harm. Saw away!
Compressed air is usually more of an issue than carb cleaner... it can ruin the nozzle check valve which generally means replacing the carb. Strong solvent based cleaners (brake cleaner etc) can be bad news for gaskets, diaphragms, etc
I read somewhere on here that the carbs on the 590 saws have a fixed high speed jet and the H adjustment is only good for the one turn that the limiter allows. If you take the limiter off and turn it past one turn it's beyond the range of the carb, so it does no good to remove the limiter. The L screw works the same as other carbs. I don't know if the 490 is like that or not...
As JD noted, compressed air has the potential to destroy check valves. I would not use it or at least use it only on low pressure to dry parts. Do not use it to blow passages clear.
I prefer cleaning carbs in an ultrasonic cleaner with nothing more than a squirt of dish soap.
The heated water and vibrations will clean out most anything.
I prefer cleaning carbs in an ultrasonic cleaner with nothing more than a squirt of dish soap.
The heated water and vibrations will clean out most anything.
