Carburetor Limiter Caps - Keep or Discard?

[lxskllr]

This references back to my "Which Echo" thread. I have some carburetor tools coming my way, and will adjust my echo after another tank or two of fuel. Reading around, I've seen references that the adjustment can creep due to vibration, and the caps should be put back after use. Is that the case, or can I just leave them off after removal?

[sablatnic]

Normally I'll discard them when I have to mess with them on my own saws - I put them back on on other saws.

[John Mc]

I left mine on. Mine had a little tab that stuck out to prevent them from turning (when the tab hit a stop). I just trimmed the tab off, so it no longer hits the stop. Withut the caps, the screws seem to drift bit over time.

The design varies from brand to brand, and sometimes with brands or for different years, so what causes a problem for some saws might not be a problem for others.

[Bandmill Bandit]

I trim and then file them off. I have even ordered and "older" new carb that doesn't have them for one saw.  

[ButchC]

If you can get the saw to run correctly with the limiters in place, (which is unlikely with any Echo I have fooled with) then leave them in place. Not because of creep but because removal or modification of the limiters will cause the dealer to deny warranty.  So you have a choice to make,  run it as best you can with the limiters or have a warranty. What I have done is run the equipment an hour or so in light use as most mechanical issues will show up in that time frame. Then when satisfied that the inner workings are happily getting along off come the limiter caps and the heck with warranty.

[lxskllr]

Revisiting this... Looking at the caps on the echo, they don't appear to move at all. They're locked in place with two ears. I'm guessing the "approved" method is pull the cap off, adjust carb, and replace so the end user can't change it?

Also, I'm not confident I can tune it by ear. Would using a tach and going by numbers give good results? I might be able to do it by ear if I had someone to help that can say "this is right", or "this is wrong". I'm not sure I can pick out the relevant sounds from internet clips.

Finally... I have an old induction automotive tach /somewhere/. Would that be sufficient, or barring that, is any old small engine tach from Amazon acceptable?

[John Mc]

Typical small engine and automotive tachs don't go high enough in RPMs to handle a chainsaw. You also want one with a fast response time, which some tachs just don;t have. I bought this tach to double check myself, since I did not trust my ear initially: DTI TECH-TACH TT-20K Tachometer.  It's not cheap ($99). There may be places to buy it cheaper, but that's where I got mine. It handles up to 20,000 RPM and has a 0.5 second refresh time.

I think finding someone to coach you would be a great way to develop your ear. When I took my saw in for repairs not long ago, the guy at the shop also tuned it for me. He did it completely by ear: four stroking out of the cut, but cleaned up in the cut with just a very light pressure on the saw. I would have liked to stay around with him a bit and have him check me out as I tuned it, but I was out of time.

[lxskllr]

I think finding someone to coach you would be a great way to develop your ear. When I took my saw in for repairs not long ago, the guy at the shop also tuned it for me. He did it completely by ear: four stroking out of the cut, but cleaned up in the cut with just a very light pressure on the saw. I would have liked to stay around with him a bit and have him check me out as I tuned it, but I was out of time.

You got me thinking... $100 is a little steep for something I won't use that often, but perhaps I can just pay a small engine shop to coach me. I'd rather give $100 to one of my neighbors than to "some company" having stuff made in China. Once I get my ear tuned, I can use it anywhere.

[HolmenTree]

Run a 1970's or 1980's Jonsered or Husqvarna and you'll learn quick how to tune the carb without a tach.  :D

Stihl are different with their vibration isolated rubber intake manifolds.... they don't shake the H L screws out of adjustment.

In 1970 the Stihl 030AV was the first saw with vibration/thermal isolated rubber intake manifolds.  ;)

[ladylake]

 

 Pull the caps, then go over to the bench grinder and grind the tabs off in about 2 seconds then reinstall for 2 reason.  To keep them from creeping and its a lot easier to get a screwdriver in those cap than on a small metal screw when the cap is gone. Tune the low so it has good throttle response, no bogging when you pull the trigger. On the high turn the adjuster out until the engine slows way down and then gradually back in until it cuts fastest in big wood. These saws have limited coils and can sound like they're 4 stroking when they run up against the coil that's why to start way rich when tuning.  I think Echo saws might come from the factory  a little richer than a few years back but every saw should be tuned right before running it. Also in hot weather they will need to be adjusted a little leaner and in cold open up the high just a little .   When you get those tabs ground off and the caps reinstalled turn both adjusters all the way in and count the turns then back to where they were so you know how it was set from the factory.  Most of these newer Echo saws come around 2 3/4 to 3 3/4 turns out and most need to be turned out a little more.  Steve

[ZeroJunk]

I have ground the tabs off of a bunch of Stihls and put them back on.

But, I have to say, I don't see what they are going to rub against or whatever that is going to have anything to do with them moving or not.

[John Mc]

I have ground the tabs off of a bunch of Stihls and put them back on.

But, I have to say, I don't see what they are going to rub against or whatever that is going to have anything to do with them moving or not.

If I recall correctly, on my saws (neither are Stihls) the H and L screws were close enough to each other that the tab on one screw would hit the shaft of the neighboring one, limiting the turn to something less than 360˚. I did not even remove my limiters to defeat them, I just reached down in with a sharp knife and trimmed the tabs off. Just took a couple of minutes.

[ladylake]

 On Echo the caps fit in the carb snug but the biggest thing is that its easier to get a screwdriver in the plastic caps rather than just the bare screw.  Steve

[lxskllr]

Is it a screw, or one of the fancy odd screws? I guess I'll find out when I take the caps off. I was gonna do it Saturday, but destroying my thumb took the wind out of my sails. Maybe this weekend.

[John Mc]

I think finding someone to coach you would be a great way to develop your ear. When I took my saw in for repairs not long ago, the guy at the shop also tuned it for me. He did it completely by ear: four stroking out of the cut, but cleaned up in the cut with just a very light pressure on the saw. I would have liked to stay around with him a bit and have him check me out as I tuned it, but I was out of time.

You got me thinking... $100 is a little steep for something I won't use that often, but perhaps I can just pay a small engine shop to coach me. I'd rather give $100 to one of my neighbors than to "some company" having stuff made in China. Once I get my ear tuned, I can use it anywhere.

Yeah, $100 isn't cheap. It's versatile enough to be used on any engine with a spark plug, but even then, I don's use it frequently.
In my Game of Logging Level 2 class they went over tuning by ear as part of the basic chainsaw maintenance section. I gather they don't cover that every time. If they get a pro-focused class, they do it. My level 2 class was mostly landowners, but enough of us were interested that the instructor spent some time on it when we requested it.

[ZeroJunk]

I have ground the tabs off of a bunch of Stihls and put them back on.

But, I have to say, I don't see what they are going to rub against or whatever that is going to have anything to do with them moving or not.

If I recall correctly, on my saws (neither are Stihls) the H and L screws were close enough to each other that the tab on one screw would hit the shaft of the neighboring one, limiting the turn to something less than 360˚. I did not even remove my limiters to defeat them, I just reached down in with a sharp knife and trimmed the tabs off. Just took a couple of minutes.

But, once you take a dry wall screw and snatch the plastic piece out, trim the tab off with a Dremel or whatever, I don't see how they keep the needle from moving after reinstallation. Don't see what they are going to have any friction against.
I do agree that they are easier to get an adjustment screw driver in.

[John Mc]

I have ground the tabs off of a bunch of Stihls and put them back on.

But, I have to say, I don't see what they are going to rub against or whatever that is going to have anything to do with them moving or not.

If I recall correctly, on my saws (neither are Stihls) the H and L screws were close enough to each other that the tab on one screw would hit the shaft of the neighboring one, limiting the turn to something less than 360˚. I did not even remove my limiters to defeat them, I just reached down in with a sharp knife and trimmed the tabs off. Just took a couple of minutes.

But, once you take a dry wall screw and snatch the plastic piece out, trim the tab off with a Dremel or whatever, I don't see how they keep the needle from moving after reinstallation. Don't see what they are going to have any friction against.
I do agree that they are easier to get an adjustment screw driver in.

The tab you trim off doesn't affect friction, it's just a stop that limits range of motion. The plastic limiter body itself - on some saws - provides some friction.

[Inaotherlife]

My brand new 361P didn’t come with caps.

But these apparently don’t sell too well, because the date of manufacture is 2015. And I just got it about 10 days ago.

Maybe the dealer took them off. I don’t know. 
Or maybe they were never on there.

Looks to have the 21 spline screw, which I don’t have the tool for yet. Plan on getting a set of carb tools soon, as I need the double-D also for my Dolmar 421.

Anyway, the manual says there’s enough adjustments for altitudes up to 1100’. And I’m around 600. So should be good in stock form.

But funny thing about this 361P is it has a different muffler than what I’ve seen that people have on their 355T. The 361P has a cat in it. So I don’t know if there’s enough adjustment if I were to get a 355 muffler or mod the one that’s on there.

[BrianT5150]

Pull the caps, then go over to the bench grinder and grind the tabs off in about 2 seconds then reinstall for 2 reason.  To keep them from creeping and it's a lot easier to get a screwdriver in those cap than on a small metal screw when the cap is gone. Tune the low so it has good throttle response, no bogging when you pull the trigger. On the high turn the adjuster out until the engine slows way down and then gradually back in until it cuts fastest in big wood. These saws have limited coils and can sound like they're 4 stroking when they run up against the coil that's why to start way rich when tuning.  I think Echo saws might come from the factory  a little richer than a few years back but every saw should be tuned right before running it. Also in hot weather they will need to be adjusted a little leaner and in cold open up the high just a little .  When you get those tabs ground off and the caps reinstalled turn both adjusters all the way in and count the turns then back to where they were so you know how it was set from the factory.  Most of these newer Echo saws come around 2 3/4 to 3 3/4 turns out and most need to be turned out a little more.  Steve

After you get the tabs ground off and reinstall the caps, does the slot in the cap have to line up with the slot in the actual adjustment screw? In other words, does the cap slide over the screw so that the screwdriver goes through the cap and into the screw or are you actually putting the screwdriver in the cap and not all the way through to the screw? 
thanks 
Brian

[lxskllr]

The plastic slot doesn't have to align with the screw slot. If you replace the caps, you can use a screwdriver to turn the plastic, and it'll turn the actual carb screw below.

Since this thread popped up again, I'll say what I ended up doing. My tophandles, I put the caps back on. The screws are easy to see, and easy to quickly adjust with a regular screwdriver. I left the caps off on the rearhandles since the screws are hard to get to, and it's easier using the splined adjustment tool when it's deep inside the case. I haven't noticed the screws creeping on the saws I discarded the caps on.

I pulled the caps using a deck screw, and cut the ears off with the knife. Quick and easy.

Finally, I ended up tuning by ear. I'm still not good at it, but I get it eventually. I start the saw off so fat a deaf man could hear it, then slowly back off the screws over time as I work with the saw. I have an easier time hearing the tune and feeling the saw when I'm working with it than I do when I'm specifically trying to tune it.

[BrianT5150]

Since I posted that question, I took the caps off and paid attention to the slot in the cap and it did not match the slot in the actual screw. The other end of the cap was hollow and looks as if it did fit right over the screw, thereby allowing you to turn the cap, which turns the screw. Thanks for the help

[Al_Smith]

I defeated the limiter caps on some model of Echo that never ran correctly since the guy bought it new .The things were marketed by the average elevation heights they were to be marketed  at. So one that mighrt sell in Colorado could be 4-5000 feet unless in the mountains would not run correctly in NW Ohio at 892 feet above sea level .It takes fuel to make power and it just was not getting enough at factory settings ,Factor in according to the EPA regulations it was supposidly not legal to change factory settings as a dealer .-----i'm not a dealer nor does Ohio have the chainsaw police force . BTW that little Echo ran pretty good after I tinkered with it .

[kenskip1]

This seems a bit odd. My Echo CS 590 new in the box, was rich from the get go. And I am at 863 feet above sea level. And yes I leaned it out on both sides.

[Al_Smith]

It kind of makes you wonder .Was it set rich to preserve it from running out lean eventually causing warrantee issues .Conversally slightly lean to pass EPA regulations ? What I do know is to the average chainsaw owner if it starts and runs is about all they care about it .