I need help deciding
- Thread starter fmrMarine
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If you have 2 screws H = hi speed adjustment L= low sp adj., will be a 3rd screw below for idle adj., then it is fully adjustable. Others have only an L low speed adjustment with out the H hi adjustment + idle screw. Later ones also had plastic limiter caps over the screws which only gives you a small amount of adjustment. They can be removed by screwing a dry wall screw in them and pulling them off for more adj.. I forget all which model carbs they used.
Good to know. I tried adjusting it yesterday and now it won't run. I can't figure out why. I backed the high and low speed out 1 turn and fiddled with the idle screw and it won't idle or barely run. When I would finally get it started it ran rough and wouldn't idle. I would have to keep giving it gas. I changed the spark plug and am using a special fuel mix that contains no ethanol. Not sure if this has anything to do with it but when I first bought it and didn't even change anything yet it ran like a champ! So I'm confused.
weedkilla
Ain't no guru of nuthin'
Let me make sure I've got this straight - the saw was running correctly and you turned both the low and high out 1 more turn?
Your carby has no plastic limit tabs on the adjustment screws, right?
Your carby has no plastic limit tabs on the adjustment screws, right?
Your right to an extent. The saw was running great. I then decided to adjust the carb to make sure the screws were where they should be. I screwed both the high and low in all the way to their seat. Then I backed them out one full turn. When I finally got the saw started after like 15 pulls it wouldn't idle or run very well. I tried adjusting idle screw next but didn't seem to make a difference. I don't see any plastic. I actually backed the idle screw out so far it came off at one point so I had to screw it back in. Not sure if it's the gas I'm using or what. I'm going to mess with it again this week
Did you count the turns in from where they were originally, so that you would know where you started? If it was running fine, you should have just fine tuned it from there.
weedkilla
Ain't no guru of nuthin'
Ok. That makes slightly more sense.
If you happened to count turns when you screwed them in - you can return to that setting.
I'm guessing you didn't, so that's lesson one. Always work out your baseline setting and write it down before you change anything.
If you happened to count turns when you screwed them in - you can return to that setting.
I'm guessing you didn't, so that's lesson one. Always work out your baseline setting and write it down before you change anything.
weedkilla
Ain't no guru of nuthin'
Brad's tuning thread - there is a link in his sig in the post above mine - has all the info you should need if you read and watch everything.
weedkilla
Ain't no guru of nuthin'
1/2 a turn is a number. It doesn't tell you if the saw is too rich or lean.
Only your ears (and a tach if you had one) will do that.
Only your ears (and a tach if you had one) will do that.
weedkilla
Ain't no guru of nuthin'
And yes, backing them out it gets richer.
Put it back where you started, then fine tune as demonstrated in the vids in the link in my sig.
Matt81
Bliss: Saw full of fuel and yard full of trees!
In Brad's sig below every one of his posts is the link to the info you seek.
In case you cannot see it or find it: http://www.arboristsite.com/community/threads/chainsaw-tuning-101.250802/
Ok guys here's the deal. After an hour of messing around with the carb I finally got the saw running again. I then made sure the L idle screw was backed out 1 turn from seat. Then I messed with the idle screw and adjusted that just to where the chain wasn't spinning. Like 1/2 turn out from where the chain stopped moving. Then I made sure the H screw was out 1 turn from seat.
I read some where though that the H screw should be adjusted when saw is at wide open throttle. Is this correct? I recall it says it should be adjusted to where its running just slightly rich or 4 stroking. I watched the videos but couldn't tell much difference. I just don't want to run it to lean and have it get to hot. Does anyone know where the H screw should be exactly?
I read some where though that the H screw should be adjusted when saw is at wide open throttle. Is this correct? I recall it says it should be adjusted to where its running just slightly rich or 4 stroking. I watched the videos but couldn't tell much difference. I just don't want to run it to lean and have it get to hot. Does anyone know where the H screw should be exactly?
Chris_In_VT
Brrraaaaap!
The H screw doesn't have a specific place, or amount of turns out where it should be. The tune changes due to weather, temperature, fuel, etc. All saws are different.
To tune the H speed, yes, you do it at WOT. You want the saw to sound like it's stumbling, or 4 stroking WOT no load. It should clean up and sound nice and smooth under a load.
See the videos in Brad's link, or lots of other info or videos on the correct sound. Some say to tune with a tachometer, I say (and others) tune so it 4 strokes and cleans up under load. Once you hear it, you'll know it.
To tune the H speed, yes, you do it at WOT. You want the saw to sound like it's stumbling, or 4 stroking WOT no load. It should clean up and sound nice and smooth under a load.
See the videos in Brad's link, or lots of other info or videos on the correct sound. Some say to tune with a tachometer, I say (and others) tune so it 4 strokes and cleans up under load. Once you hear it, you'll know it.
That is correct.
Some of my saws I can clearly hear the stumble and others I can't. Such as my 026. The easiest way I have found to tune the h needle on saws I have trouble hearing 4-stroke on is to make it really rich in the cut (easier for me to hear 4-stroking) and lean it out from there.
Its also easier for me to hear the change in tune when I'm wearing ear plugs.
Its also easier for me to hear the change in tune when I'm wearing ear plugs.
