Used the wrong 2 stroke oil in ECHO CS-490

[Echoman]

I have an Echo CS-490 that I used standard 2-stroke oil in and by doing that the saw no longer runs. I can pull the rope to start, but it pulls too easy. I was only able to run the saw for a short time with this oil before it failed on me.

I'm wondering what I would need to replace because of this.

I'm thinking the cylinder head and replacement rings for the piston.

Thank you,

 

[Bob Hedgecutter]

What do you mean by "standard 2-stroke oil"?
In my experience, most 2-stroke equipment will run fine on standard hardware store type oil- it may not be the best, but if the ratios are somewhere within the saw and or oil manufacturers spec, they might burn dirty, perhaps not to full performance and not be the most perfect mixed fuel to be running- but they should still run.
Now if you used a common "garden" variety oil in the mix at a ratio suggested for some kind of fancier full synthetic that is above the max recommended 50:1, you might have some problems.

Pull the muffler off and take some photos of the piston through the exhaust port- that will tell most of the story.
If it was indeed the fuel mix leaning the saw out, I dare say piston and ring/rings minimum and you might be able to clean the transfer of melted piston from the interior of the cylinder well enough to save it.
If there are gouges through or bits of plating flaking off the interior of the cylinder- you will need one of those as well.
About then it becomes a question of economics- is it worth trying to find and buy the repair parts, versus the cost of a new saw?

 

[Echoman]

What do you mean by "standard 2-stroke oil"?

I've always used 2 stroke oil that was recommended for the Echo chain saw. It could have been a garden variety, but this is when it failed. I will take your recommendation's and start from there.

Does anyone know where I can find a service manual for the CS-400 or CS-490?

Thank you so much for providing me this information, I surely appreciate this.

Thank you,
Kelly

 

[huskihl]

Oil mixed at the proper ratio didn’t cause the failure, no matter the brand. They are tuned extremely lean the way they are sold and don’t live long if the owners don’t recognize that

 

[Echoman]

That's really good to know. It's been a few years since I looked at this chain saw. I will put some new gas in it and see what happens. I was thinking it was froze up, but I pulled the starter rope once last night and it did pull no problem. I will also take a look more closely at things on it and see what I find out.
Everyone, Thanks for the Help!

 

[huskihl]

Remove the muffler and take a look at the piston for vertical scoring. If it’s already scored from running lean, you’ll just make it worse by running it more. If that’s the case and you catch it early enough, usually you can replace the piston and clean up the cylinder. If not, you may end up replacing the cylinder as well

 

[Echoman]

OK, sounds good - I will do that. Thanks for the update.

 

[Echoman]

I'm trying to remove the muffler on the chainsaw. It's supposed to have (4) bolts, but I only see (2) on the bottom of the muffler. Does anyone know where (2) are located? I'm thinking I may have to take off the casing on the saw to located these.

 

[Echoman]

I was able to find where the other (2) screw are location. They are in the tubes that I was thinking were exhaust ports.

 

[RedneckChainsawRepair]

Bet just tuned to lean or had a air leak somewhere. Long as it was a good FB FC FD oil name dont really matter. FD the best of best.

Had to clean up a 490 cylinder I took on trade. Had a air leak.

 

[Echoman]

Hello, I was able to get the muffler removed last night and take a look at the piston. I'll see how much of a picture I can get on this.

The saw that I have was not used much, maybe a month or 2, and it looks like new. I really didn't see any scorching or scratches on the cylinder, so I think I should put some new gas in it and see what I can tell. I haven't touched the saw in a couple of years.

I'll update what I find out.

Thank you,

 

[Echoman]

Put some new gas in it today and got it started. The saw has no power, the chain rotates to slow to cut anything. Maybe piston rings?

Thank you,

 

[Bob Hedgecutter]

If it starts and runs- compression is enough to get it going- new rings might up the compression, but will not increase the revs and chain speed.
You will not see scoring on the cylinder through the exhaust port on the CYLINDER as it will form on the cylinder wall above and below the exhaust port if it has been run lean- intake side might look fine and dandy- the exhaust side of the PISTON through the exhaust port will tell the story.

 

[Echoman]

I had taken off the muffler, but was unable to really see anything much, the piston looked good through the exhaust port. Maybe if I take off the cylinder head cover this would give me a better look at things. Everything looked like new through the exhaust port. Also throttling the saw when started seemed like it had very little power.

 

[Bob Hedgecutter]

Well, if the piston looks good, leave it as be. (photos will confirm)
Could be you are getting rid of old fuel in the fuel lines and carb chamber and power will pick up when the fresh gas is sucked through- or the old gas may have gummed up your carb internals and be restricting fuel flow.

 

[huskihl]

Is the brake on?

 

[Bob Hedgecutter]

Is the brake on?

Sometimes I forget the simple things.

But was mention above of the chain moving- but too slow to cut anything.

 

[Chainmale]

Is the spark arrestor screen clean/unblocked?

 

[Echoman]

Well, I'm wondering that too now if the brake was on. I don't think so since the revving of the motor was pretty high and sounded like crap. I am trying to get the cylinder head off but there's something in the cylinder port from the carburetor side. Having trouble removing that. Is there a trick to this?

 

[Echoman]

I was able to get it off. Maybe removing the carb at the same time would work better? I have some pictures attached of what the piston and cylinder look like. I'm not sure if it looks bad or good. Please look at the pictures and see what you think.