Stihl 084 won’t idle

Gravely009

Gravely009

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Mornin!
I’ve been slowly working my way through an 084 and I can’t get it to idle. Fires on choke, will start the next pull and run a bit but won’t stay running for more than a few seconds. Then it’s gotta go on choke again to fire again. I have cleaned the carb and put a new kit in, replaced the fuel and impulse lines (fuel line was cracked, impulse was not), set the flywheel gap with a business card and gapped the spark plug to .5mm (couldn’t find the correct gap for an 084 on google and decided it couldn’t be much different than an 088). Compression is pretty good. Got it up to 150 on The gauge and decided to quit pulling on this monster. The next step is a pressure and vacuum test correct? I’ve read enough posts on how to do it but I don’t have a pressure/vac set up. Is a harbor freight special good enough to do the job? Do I need something better? Or should I just strip the saw down and see what a saw shop would charge me to do it? Any advice would be very much welcomed. Pics for attention.
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Robin Wood

Robin Wood

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Mornin!
I’ve been slowly working my way through an 084 and I can’t get it to idle. Fires on choke, will start the next pull and run a bit but won’t stay running for more than a few seconds. Then it’s gotta go on choke again to fire again. I have cleaned the carb and put a new kit in, replaced the fuel and impulse lines (fuel line was cracked, impulse was not), set the flywheel gap with a business card and gapped the spark plug to .5mm (couldn’t find the correct gap for an 084 on google and decided it couldn’t be much different than an 088). Compression is pretty good. Got it up to 150 on The gauge and decided to quit pulling on this monster. The next step is a pressure and vacuum test correct? I’ve read enough posts on how to do it but I don’t have a pressure/vac set up. Is a harbor freight special good enough to do the job? Do I need something better? Or should I just strip the saw down and see what a saw shop would charge me to do it? Any advice would be very much welcomed. Pics for attention.
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Have you tried raising metering lever a little? How does it idle on sides?

Sent from my INE-LX2r using Tapatalk
 
Gravely009

Gravely009

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Have you tried raising metering lever a little? How does it idle on sides?

Sent from my INE-LX2r using Tapatalk
I have not tried that, just back off that screw a little bit? And idk about the side, doesn’t run long enough to move it around. Don’t wanna ruin the pc trying to keep it running if there’s an air leak
 

MFV

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Mornin!
I’ve been slowly working my way through an 084 and I can’t get it to idle. Fires on choke, will start the next pull and run a bit but won’t stay running for more than a few seconds. Then it’s gotta go on choke again to fire again. I have cleaned the carb and put a new kit in, replaced the fuel and impulse lines (fuel line was cracked, impulse was not), set the flywheel gap with a business card and gapped the spark plug to .5mm (couldn’t find the correct gap for an 084 on google and decided it couldn’t be much different than an 088). Compression is pretty good. Got it up to 150 on The gauge and decided to quit pulling on this monster. The next step is a pressure and vacuum test correct? I’ve read enough posts on how to do it but I don’t have a pressure/vac set up. Is a harbor freight special good enough to do the job? Do I need something better? Or should I just strip the saw down and see what a saw shop would charge me to do it? Any advice would be very much welcomed. Pics for attention.
View attachment 919518View attachment 919519View attachment 919520View attachment 919521View attachment 919522View attachment 919522View attachment 919523View attachment 919524View attachment 919525
Does it rev up immediately? Mine was the oil seals I changed them out problem solved. That being said I took mine all the way down and replaced the bearings at that point and that paid off because the ones I took out sounded pretty bad.
 

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Gravely009

Gravely009

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Does it rev up immediately? Mine was the oil seals I changed them out problem solved. That being said I took mine all the way down and replaced the bearings at that point and that paid off because the ones I took out sounded pretty bad.
Yeah it starts, revs, (you can keep it going a bit with some throttle) then dies. I’m guessing it is the seals.
 

MFV

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Yeah it starts, revs, (you can keep it going a bit with some throttle) then dies. I’m guessing it is the seals.
Yeah mine was out of control reved high and you could half way keep it running with the throttle. I ruined my first set of seals because I didn’t use the tin can trick to slide them on . How long have you had the saw?
 
Bob Hedgecutter

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You can remove most the parts and then take the powerhead to your Stihl service centre and they will pressure test it for you- for a fee, but perhaps cheaper than buying a Mityvac for one saw.
But it might just be of that age now that it needs a freshen up of all the wear items and potential leak sites.
As suggested above, if you are going to do seals- think about doing bearings at the same time, gaskets and rubber bits. Freshen it all up and you can rest easy that all is good- not chase your tail when the next wee problem crops up.
 
Gravely009

Gravely009

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Yeah mine was out of control reved high and you could half way keep it running with the throttle. I ruined my first set of seals because I didn’t use the tin can trick to slide them on . How long have you had the saw?
I picked it up 3 or 4 weeks ago
 
Gravely009

Gravely009

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You can remove most the parts and then take the powerhead to your Stihl service centre and they will pressure test it for you- for a fee, but perhaps cheaper than buying a Mityvac for one saw.
But it might just be of that age now that it needs a freshen up of all the wear items and potential leak sites.
As suggested above, if you are going to do seals- think about doing bearings at the same time, gaskets and rubber bits. Freshen it all up and you can rest easy that all is good- not chase your tail when the next wee problem crops up.
Reallyyyyy trying to not have to split the case, never done it before and super don’t want to buy the tools if I don’t have to.
 

MFV

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Reallyyyyy trying to not have to split the case, never done it before and super don’t want to buy the tools if I don’t have to.
I felt the same way but got my machinest at work to help me out but my PTO bearing was bad same situation I bough it used and only used it a few times before rebuild. Problem solved
 
tomalophicon

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Kinda? I didn’t mess with it too much, definitely would need some carb adjustments but I think it would. I’m a little hesitant about running it too much if there is a leak.
Fair enough. I'd test for leaks first. There's a cheap ebay pressure/vac pump that works quite well and comes with a range of fittings. I paid $37AUD. Could be the same has Harbour Freight.
Inability to idle could also be a carb issue.
 
Bob Hedgecutter

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Reallyyyyy trying to not have to split the case, never done it before and super don’t want to buy the tools if I don’t have to.
Fair enough- strip it down to the point of the cases being ready to split- take it to a shop and ask them to split the case, fit new bearings, put the case back together with a new gasket and install the oil seals for you.
Then it is just Meccano for grown ups.
 
Bob Hedgecutter

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Translate that into American, please.
You guys never had Meccano sets?
How else do you learn to bolt things together? Is this why American manufacture fell away? You only had Duplo (assuming you didn't get Leggo either?) and only leaned to click block build? :laugh:
 
Maintenance supervisor

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Did you clean out thr brass tube for the impulse line? I've found them blocked. Is the mating flange for the carburetor good? Cracks in the boot?
Start with the simple stuff first.
 
Woodslasher

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You guys never had Meccano sets?
How else do you learn to bolt things together? Is this why American manufacture fell away? You only had Duplo (assuming you didn't get Leggo either?) and only leaned to click block build? :laugh:
I learned how to bolt things together on the many project cars my brother dragged home, most other people I've met around my age don't know how to bolt stuff together.
 
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