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Echo trimmer bog problem

Posted by boltonranger (My Page) on
Thu, May 7, 09 at 11:44

Alright this is a 2 stroke Echo trimmer.
21cc; single ring piston.
Light scratches no deep scores in cylinder.
The cylinder has it's cross-hatching still.
I rebuilt the carb & replaced the crank seals.
Compression is 125 psi.
I read elsewhere that these trimmers typically have 120-130 psi.
I did replace the ring but compression did not seem to improve.
The new ring only got to 100 psi. The old was 125.
This may have been the seal on my compression tester - I could not tell.
My tester screws in too far before seating so I used some teflon tape on the threads and didn't screw in too far to avoid hitting the piston.
Difference between old and new ring is negligible thickness-wise.
Old ring has chamfering on upper and lower edges
Put old ring back in when new ring did not improve compression.

Set coil to .012" air gap. (Would larger gap (.014-.016) change anything?)

Here's the trouble:
Got it running; idles well.
Will accelerate and hit wot (8k-10k wherever I set it)
but has about [B]a one second bog[/B] on the way up.
If I squeeze the trigger slowly it comes up okay but if I goose the throttle it bogs just a little as it takes off. Enriching the hi only works to a point. Never quite enough to make the small bog go away.
I've tried enriching the low jet to the point the idle is poor,
but it does not help.

Does this sound like symptom of the metering rod setting being off a little?
Or something else?
I can use the trimmer; - just real annoying to have the small bog considering the time I spent on it.
-Appreciate your thoughts.
-br


Follow-Up Postings:

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RE: Echo trimmer bog problem

I am pretty sure you know more than me. So I am not making any suggestion, just asking.

It sure sounds like it is still the carb problem. When you rebuilt the carb, did you use carb cleaner and force air to blow all the small opening? Also there are some small moving parts, could it still have a little dirt and stick? Don't think you have jet type of problem, just slow response, but it'll get there and work good.

Only thing I can think of is open the carb up and clean it one more time, I like to use can air spray that I use with computer, you can get it in computer store. I like the small tube that you can direct the air to very small holes. As I said, you probably know more than I do. Just talking!!
Cheers


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RE: Echo trimmer bog problem

I would supect a diaphram problem. I know you probably know this but I got ask; did you put the diaphram on first then the gasket? if not the gasket is thick enough to not make the diaphram work properly releasing the needle valve.


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RE: Echo trimmer bog problem

Yes diaphragm first; then gasket.
Will re-open carb tomorrow night and re-check all.
Thank you both for your replies.
Will let you know what I find.
-br


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RE: Echo trimmer bog problem

I think now that the clutch springs are weak.
If I goose the unit while it is spinning above idle (like while it is winding down from full throttle, It takes right off.
If I remove the shaft from the motor it doesn't bog if I rev it from idle.
Thank you all
-br


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