New Echo 3510 carb tune issue

[freekeydiver]

I ran a few tanks of gas and did some easy limbing. Then I slightly opened the muffler exhaust. I removed limiter caps and attempted to tune carb. I set low screw at mid point where if revved the most, then set idle where chain just stopped moving. It will start and idle but bogs down/dies if I give if throttle. I’ve messed w/high screw in and out to no avail. It wont rev and dies.
Any advice?I’m pretty resigned to taking tk a shop although there’s no Echo dealer nearby. Purchased online.

 

[echomeister]

They are hard to tune. I got advice here to tune the low for good throttle response then set the idle. My trouble was the idle was too low so when L was set properly it still would not idle. Still won't idle when cold. I have resigned myself to having to spend a minute nursing the throttle when first started before it will idle. It's a very good saw though overall.

 

[Vintage Engine Repairs]

Setting the L for the fastest rpm is your start point. From here open it 1/4 of a turn and adjust your idle screw to compensate.

 

[mountainlake]

Open up the low until it doesn't hesitate when you squeeze the throttle, you most likely will have to set the idle higher. Steve

 

[SE_GA_Sam]

They are hard to tune. I got advice here to tune the low for good throttle response then set the idle. My trouble was the idle was too low so when L was set properly it still would not idle. Still won't idle when cold. I have resigned myself to having to spend a minute nursing the throttle when first started before it will idle. It's a very good saw though overall.

I'm having the same issue. I tuned the carb per the service manual procedure (set low jet to fastest idle, run idle speed up with TAS to 3900, rich low jet to bring it back to 2800-3000) and everything runs great when its warm. However, it won't idle when cold. Like you, I have to nurse the throttle until it's warmed up a bit or it dies.

Interested to see if this just is what it is, or is there a better way to tune it?

 

[Vintage Engine Repairs]

I'm having the same issue. I tuned the carb per the service manual procedure (set low jet to fastest idle, run idle speed up with TAS to 3900, rich low jet to bring it back to 2800-3000) and everything runs great when its warm. However, it won't idle when cold. Like you, I have to nurse the throttle until it's warmed up a bit or it dies.

Interested to see if this just is what it is, or is there a better way to tune it?

Is the engine brand new?

New engines can be very finicky, they won’t idle down the best, they tend to be a little unsettled etc.

 

[SE_GA_Sam]

Is the engine brand new?

New engines can be very finicky, they won’t idle down the best, they tend to be a little unsettled etc.

It's still fairly new. I'd estimate 6-8 tanks of fuel through it. It has always been a bear to start when cold, which is why I finally pulled the limiter caps and started tuning the carb.

 

[Vintage Engine Repairs]

Ah that should be well broken in by now. Upload a video of you starting it, it idling, going to full throttle and returning to idle. We’ll be able to give you much better advise if we can hear the tune. Be a few metres away from the camera with the muffler pointing towards it.

 

[coffeebrk]

I've had several cs3510's. Found them easy to start and tune. Sold 2 and have one to keep. The one left still has the limit caps on.
My 2 cents....
Fresh rec gas w/red armor
When it pops and you pull trigger, before you pull again pull out choke, no trigger, push the choke lever back in. This will set high idle w/o choke.
If you can't get it to cold idle turn the idle "T" screw in until it idles when cold.
Then you can begin adjusting L&H respectively.

 

[rmh3481]

Which carb? WT-1239? Some of the small echo saw's have the Walbro 589 style accel pump like used on the reed valve 302/305/306/341 and related. I have seen that accelerator pump called a starting system in some of the books. After you pump the purge bulb a couple times, pump the throttle trigger to get the acc pump O ring wet with fuel so it wont leak any air. If you want to get technical, the carb leaks external barometric pressure into the metering side thru the accel pump which causes a lean run engine condition no matter where your limiter jets are set. You can replace the carb but they all seem to act this way once in a while after they have been hot a few times. That is why I say to pump the throttle a couple of times after you pump the purge to get the insides all on the same page with fuel.

All the manufacturers are having major trouble getting two stroke engines to pass biden epa emissions. When the engine is idling off the jets it will pass emissions, but it wont transition off the super lean settings demanded by the epa. The additional fuel provided by the accel pump is what allows the engine to actually transition and run as you would expect.

Attached below is the echo supplemental service information that has the jet settings listed at the bottom of page 3. See if those settings dont get you in the ballpark and remember to pump the throttle at the first start of the morning when your done purging the air out of the lines.

 

[toppers]

If you need to keep giving it gas or it dies, increase the idle screw a bit more, maybe to where the chain barely moves at idle.

 

[SE_GA_Sam]

It has the WT-1239 carb. Purge valve has been pumped so it's full of fuel. Using 92 octane pre mix.

First video is trying to get it started. Pulled the plug and vented the cylinder. Second video shows the next attempt, with idle and WOT. Both start attempts have the high idle engaged.

Apparently I can't upload videos, so I'll put them on YouTube and embed the links

Start attempt:


Idle and WOT:

 

[coffeebrk]

Turn up your throttle screw

 

[coffeebrk]

Finally stopped raining
3 pulls cs3510 started right up
Tacho reads 2880-3000 idle
I confirmed my tach couple of weeks ago when I picked up my new 550xp mkll
Owner was kind enough to check saw with his tach and mine very close

 

[SE_GA_Sam]

I leaned the low jet a half turn and that seemed to have fixed the cold starting difficulties.

Screwed in the TAS to bring cold idle up to ~3000 rpm, and it idled fine after unlatching the high idle trigger.

Didn't have a chance to do any cutting with it, so we'll see if any other adjustments are needed to the high jet.

 

[Vintage Engine Repairs]

Yes you were a bit rich on the L screw. Always start with finding lean & rich drop, then adjust idle
to 500rpm+ spec then richen the L screw until you get that nice bouncy burble. Check throttle response, adjust accordingly and set high.

The only time this doesn’t apply is dependant carburetors, they need the H adjusted first.