Echo - Can't find rattling source?

[daveslandscaping]

Just put some new parts on my echo SRM2400 and cleaned it up. Since it was apart, I decided to try to find the source of a very loud rattling that it has had for a while when it is running at anything other than idle. It makes it about twice as loud as it should be. All the bolts on the machine are tight and I even tried running it mostly taken apart. It appears to be origination from the muffler area.

I took the muffler apart as much as I could running it without the spark screen in it, wedging things between the engine and the heat shield. Still, the noise persists. There doesn't seem to be much to the internals of the muffler that could be loose and rattling, but I can't figure out where else the noise could be coming from.

Any ideas? I am thinking of just buying a muffler and seeing if thats it, but I don't wanna spend the money and find out thats not it. Think there is anything in the muffler that could be loose?

[daveslandscaping]

PS - I just looked it up and the muffler is 40 bucks. Not worth the investment on this machine if thats not the source.

[Breezmister]

PS - I just looked it up and the muffler is 40 bucks. Not worth the investment on this machine if thats not the source.

If you have narrowed it down to the muffler, chances are that one of the baffles in the muffler has come loose. If you have the muffler off and shake it, you should not hear any noise rattling around it.

For what it's worth, about 3 years ago I had a Tanaka come in that was seized up, after checking it over, I found a small piece of the baffle screen that had been sucked back into the cylinder. Never saw one like that before or after, so it might have been a fluke.

[daveslandscaping]

If you have narrowed it down to the muffler, chances are that one of the baffles in the muffler has come loose. If you have the muffler off and shake it, you should not hear any noise rattling around it.

For what it's worth, about 3 years ago I had a Tanaka come in that was seized up, after checking it over, I found a small piece of the baffle screen that had been sucked back into the cylinder. Never saw one like that before or after, so it might have been a fluke.

When I had the muffler off I did try shaking it. No noise. There is pretty limited baffling in the muffler, I can see most of the guts with the spark screen off. I agree, I can't think of anything else it could be so it must be the one baffle that I can't see resonating as soon as I get off idle.

If anyone thinks differently let me know. Otherwise I'll swallow the 40 bucks tomorrow morning.

[Breezmister]

When I had the muffler off I did try shaking it. No noise.

Have you checked the clutch or the clutch cup ? Is the noise a rattle or a ringing ?

[daveslandscaping]

Have you checked the clutch or the clutch cup ? Is the noise a rattle or a ringing ?

I think its more of a rattle. It kicks in as soon as you get off idle and is increasingly irritating as you increase RPM. I have not messed with clutches on any trimmers, are they easy to get to without taking the whole unit apart? What noises do the clutches make when they are going?

I think I'll mess with it some more this weekend. Maybe trying running it without the muffler on, then running it without the heat shield, etc. to see if I can narrow it down any further.

Thanks for the help

[Breezmister]

I have not messed with clutches on any trimmers, are they easy to get to without taking the whole unit apart?


Depends on how you define easy. Do you have a manual or a parts break down ? If you don't, Echo has them on their website for down load. But yea, you would have to take the engine off of the fan case to get to the clutch.

What noises do the clutches make when they are going?

Depending on the problem, it will sound like a ringing of a bell. I guess that is the best way to describe it.


I think I'll mess with it some more this weekend. Maybe trying running it without the muffler on, then running it without the heat shield, etc. to see if I can narrow it down any further.


That is what I would do, I hate to throw money at a problem until it is fixed. That can be a expensive learning curve :dizzy: