Oh- never say never from experience. Especially if stuck closed.
Help Request on Stihl 028 AV Super Wood Boss - Bogging
- Thread starter cbrTodd
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Here are pictures of every face of the carburetor with every marking I can find. There's also a cast "M22" on the face where the needle valve sits, but I didn't take a picture of that since it's internal to the carb. I suspect that the important ones are the stampings "WT 16B B7" on the face with the fuel line barb, but I'll let you be the judge.
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I would definitely be interested in carb manuals if you have them! I'm sure that would be helpful.
I think I see what you're talking about but there's no chamfer on the top of the cutting edge. Just some dark colored gunk on top and bad lighting. It was dull though, but 5 strokes with the 3/16 file at 25 degrees on each tooth and it was back where it should be (I had to look at the chain package I keep in the case).
On the clutch, yes it had some discoloration but it came off very quickly with sandpaper. I reassembled it using the Stihl carburetor and it still ran like junk and bogged, but it made a few more chips before doing so.
So I put the 'good' rubber parts back in the Amazon carb body and tried to start / tune it and that was noticeably better than the Stihl carb. It still doesn't want to idle any more and it's got no power once it gets to full speed, but it will get there easier without load. You could even cut some with it if you were patient enough to plug along at about 1/3 the intended operating speed. I'm not that patient.
At this point I'm willing to go get a true Stihl / Walbro OEM replacement and give that a shot. So since folks are saying that what's listed in the manual may or may not be right, can you tell if it's the 1118 120 0601 from the pictures in the last post? If not, how do I find out what it is? Can the dealer tell from the saw's serial number?
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Where is this valve located? Is it in / under the brass piece at the top of the carburetor near where the W is stamped in this picture? I know I get lots of flow out of there when I spray brake cleaner in the hole for the High speed adjusting screw, but I have no idea if it's the right amount.
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SteveSr
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This valve is located in the main venturi nozzle. Some were rubber discs others were made out of woven fiberglass. If stuck open the saw won't idle with the correct carb settings. If stuck closed it will bog not rev up.
A WT-16 is an older pretty simple carb to troubleshoot. Main nozzle valve can be checked with your mouth and a suitable piece of tubing. However if this carb uses a rubber disc and you used compressed air on it that disc has likely left the building for the stratosphere.
Here is a Walbro service manual...
All good mate, you mentioned stuck open which would flow fuel but won’t start and idle but it was, that’s all 👍
1119 358 7700
some dumbaszz used tygon and its collapsed killing your fuel delivery, replace the fuel hose using the part # given. It can clearly be seen being used in your video, if the impulse hose is tygon aka yellow/clear replace it with stihl hose too!!
some dumbaszz used tygon and its collapsed killing your fuel delivery, replace the fuel hose using the part # given. It can clearly be seen being used in your video, if the impulse hose is tygon aka yellow/clear replace it with stihl hose too!!
The only Tygon hose on the saw is the vent tube. I used it to do the pressure / vacuum checks because I could thread it into the hose barb on the case, but it is not used for either the fuel supply or impulse line.
then i'd replace the ignition coil and plug if the fuel hose is good and not collapsing, cracking or the fuel filter is not clogged up.
Good lord that chain is fuked up! in a way that will result in it biting in and likely bogging down a underpowered saw. Ever try filing a chain? there are modern filing jigs sold by stihl and pferd that make it pretty idiot proof.
Take it easy on him mate, he’s learning. We’ve all been there.
Not meant as a insult! that chain, and clutch got hot! I meant it as a question, if filed incorrectly it will bite in deep and bog a under powered saw down.
That brass peace in the carb throat is the check valve for the main H feed in the carb
cookies, if you had read the earlier posts you would have seen that I already replaced the coil once, it made no difference, so I went back to the original.
I ran with the fuel filter and vent hose screw removed to eliminate those possibilities. No change.
On the chain, yes those pictures are from before I sharpened it, but by no means was it bad enough to be 'fuked up'. It was just dull. I use the Oregon file jig to set the angle and only touch the rakers if they protrude out the gauge across teeth, which these don't. I don't know what you think you see, but now after sharpening (which I don't have pictures of) the chain would cut fine if the engine had power. I have sharpened the chain on this saw for a few years when the saw still cut ok, and multiple chains on my MS180 hundreds of times and it continues to cut fine, so my sharpening ability isn't quite as bad as you seem to think.
I ran with the fuel filter and vent hose screw removed to eliminate those possibilities. No change.
On the chain, yes those pictures are from before I sharpened it, but by no means was it bad enough to be 'fuked up'. It was just dull. I use the Oregon file jig to set the angle and only touch the rakers if they protrude out the gauge across teeth, which these don't. I don't know what you think you see, but now after sharpening (which I don't have pictures of) the chain would cut fine if the engine had power. I have sharpened the chain on this saw for a few years when the saw still cut ok, and multiple chains on my MS180 hundreds of times and it continues to cut fine, so my sharpening ability isn't quite as bad as you seem to think.
then the picture is misleading, what I saw was a very low depth tooth in your photos
https://prnt.sc/8CLDMmHgQuND
In your cutting video it sounds like the saw is not running at max rpm at wide open throttle, it should free rev instantly to 12,500 rpm then burble a little from excess fuel at that rpm. You could also have damage to the rings/piston you can not see. Can you bog the engine at max rpm using the H needle?
https://prnt.sc/8CLDMmHgQuND
In your cutting video it sounds like the saw is not running at max rpm at wide open throttle, it should free rev instantly to 12,500 rpm then burble a little from excess fuel at that rpm. You could also have damage to the rings/piston you can not see. Can you bog the engine at max rpm using the H needle?
it sounds like the saw is not running at max rpm at wide open throttle, it should free rev instantly to 12,500 rpm then burble a little from excess fuel at that rpm.
That is what I mentioned in one of my previous posts.
and the saw sounds to me like it is not reving up as fast as it should out of the wood unloaded when you are piss reving it.
Do you have a good reliable accurate electronic tach? (to see what the max rpms are when tuning the carb)
I agree that the saw should accelerate quickly to max speed and the intermittently try to 4 stroke when it gets there because it is slightly rich. As of last night's testing, when I get it there with carb tuning unloaded, it is still slower to speed up than it should be, and it bogs immediately when load is applied. Turning the H screw out less than 1/8 turn additional will make it bog down appreciably both unloaded and in wood. I don't have access to a tach that will work on this.
I just called the closest Stihl dealer and the carb was discontinued years ago. I don't trust myself to go any deeper in the OEM one because I know I will never get those plugs to seal again. What's the least bad aftermarket option?
I just called the closest Stihl dealer and the carb was discontinued years ago. I don't trust myself to go any deeper in the OEM one because I know I will never get those plugs to seal again. What's the least bad aftermarket option?
You can buy 028 carbs on eBay for less than $15
I have used three or four and they have worked fine.
Try sawzilla parts and ask them if the carb they have will fit your Stihl
they show a carb for several 028 models.
https://sawzillaparts.com/
or as zero junk says since you are up against the wall with a cracked dinosaur egg and do not know for sure it's the carb maybe go with another $15 China clone as a test.
I do not like using China stuff on a Stihl but you may not have any other choice, especially
since your is obsolete. I sometimes try a clone as a test only on a Stihl and if I get a good run then I try repairing/replacing with the OEM. (I just do not trust clones due to leaning out later)
You asked about removing welch plugs. I'm not telling you to do such but when I'm FORCED to do such as a last chance I carefully make a itty bitty hole in the welch plug, take a steel o ring pick or similar tool and gently pull the plug then to re-install I place the plug on a piece of leather and use a round end punch or a ball bearing from my assortment and reform the plug put it in place and use the normal welch plug re-install then I have some 2 part non-runny epoxy I use to seal the plug hole and the edges. You can also use permatex silcone gasket maker as a temp test but the permatex will not stay on for long term like the epoxy. the permatex is only used on the plug just get a seal for a test run and can be easily removed for the epoxy later.
Just be careful and do not get the sealant inside when sealing.
Been doing this for years on both the steel and aluminum welch plugs. I very seldom have the correct size welch plug in my saved welch plug assortment.
But I think you need to test another carb FIRST and if goes ok then maybe go deeper into your WT16B. I seen a Stihl OLD part number on your carb as a 1118 120 0601.
You can maybe also try the want to buy section of this site if you want another WT16B
they show a carb for several 028 models.
https://sawzillaparts.com/
or as zero junk says since you are up against the wall with a cracked dinosaur egg and do not know for sure it's the carb maybe go with another $15 China clone as a test.
I do not like using China stuff on a Stihl but you may not have any other choice, especially
since your is obsolete. I sometimes try a clone as a test only on a Stihl and if I get a good run then I try repairing/replacing with the OEM. (I just do not trust clones due to leaning out later)
You asked about removing welch plugs. I'm not telling you to do such but when I'm FORCED to do such as a last chance I carefully make a itty bitty hole in the welch plug, take a steel o ring pick or similar tool and gently pull the plug then to re-install I place the plug on a piece of leather and use a round end punch or a ball bearing from my assortment and reform the plug put it in place and use the normal welch plug re-install then I have some 2 part non-runny epoxy I use to seal the plug hole and the edges. You can also use permatex silcone gasket maker as a temp test but the permatex will not stay on for long term like the epoxy. the permatex is only used on the plug just get a seal for a test run and can be easily removed for the epoxy later.
Just be careful and do not get the sealant inside when sealing.
Been doing this for years on both the steel and aluminum welch plugs. I very seldom have the correct size welch plug in my saved welch plug assortment.
But I think you need to test another carb FIRST and if goes ok then maybe go deeper into your WT16B. I seen a Stihl OLD part number on your carb as a 1118 120 0601.
You can maybe also try the want to buy section of this site if you want another WT16B
As long as you can get the welch plug shape to fit your carburetor, don’t hesitate to remove them. People say how difficult it is to reseal them, but it’s really not. Place them down and tap them until they are flat, and you’ll be good to go.
If you run ethanol in your fuel, avoid using any sealant. If you don’t use ethanol, apply a thin layer of CA glue or nail polish onto wax paper, dab the welch plug in it, and quickly place it over the drillings before tapping it flat.
Shying away from learning will only hinder your improvement. I suggest removing welch plugs from the carburetors you service until your comfortable with the process. Avoiding it and running into issues like this and being reluctant to fix it never sees you grow and improve.
