I just got this stihl 028, it was sitting in a shed for god knows how long. It was dirty, like it had been used put up, repeat. I took it home dumped all liquids out, cleaned it up. Compression feels good when I pull the rip but I don't have the equip to test it. I changed the spark plug, got a new air filter for it, got a can of stihl hi performance pre mix gas, cleaned out cylinder and carb with carb cleaner. Will spare details on all the gunk I had to clean off bar, housing and all of that. Set carb to factory, nothing. I've been tweaking it here and there. I've gotten it to start but then it stops, got it to idle but a fast idle then it shuts off. I'm thinking even though the fuel filter doesn't look bad I'm going to replace and thinking of either buying a new or rebuilding the current carb. I work on most of the two-cycle equipment at work and have rebuilt carbs before. But not getting instant gratification out of this saw is frustrating me. I've gotten it to idle adjusted it, bogged down when I hit the throttle so of course went to adjust that then it wouldn't start. I get one thing working then when I adjust the other it stops working all together.
Stihl 028 WB Problems
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Jon1270
Minister of Fire
Have you checked the condition of the fuel line? Sitting for a long time with gas in it can make the rubber line inside the tank very soft, so it can tear, collapse, kink, etc.
How did you clean the carburetor? Did you disassemble it and spray carb cleaner through the jets, internal screen, etc. or did you just spray some down the throat of the assembled carb? If you took it apart, what was the condition of the gaskets and diaphragms?
How did you clean the carburetor? Did you disassemble it and spray carb cleaner through the jets, internal screen, etc. or did you just spray some down the throat of the assembled carb? If you took it apart, what was the condition of the gaskets and diaphragms?
Jon1270
Minister of Fire
Also, can you be more specific about these?
What, exactly, did you adjust here :
and here:
What, exactly, did you adjust here :
and here:
I half assed it and only sprayed down the throat, and hosed out the cylinder with carb cleaner (exhaust was off so the cleaner could flow out) let all of that dry before reassembly. as for "adjust" I set the H L and LA to factory. When I got it to Idle I adjust the L to get it to idle correctly once it was idling right I hit the throttle and it bogged down so I adjusted the H went to restart the saw and I had trouble getting it to start and it wouldn't idle so started at square one back to factory. Did this several times, but can not get it to idle correctly or if I do if I adjust the H and it shuts off then nothing wants to work. Oh and fuel line is good filter looked ok was just being lazy not changing it. And I was hoping new fuel/oil mix and carb cleaner would suffice but I'm sure since I took the lazy route I need to take carb apart. Was just going to buy the rebuild kit for it and rebuild it.
I'm sure the answer to my question is the carb is varnished or clogged. Will probably cut out the middle man and just replace fuel line and filter together a long with rebuilding the carb. After that's done and assuming I get it started and adjusted correctly it should work. But if after all that it doesn't work then I'd be stumped. I've fixed two other stihls and an old blue homelite super xl automatic before. Was just hoping that this one would be easy.
Jon1270
Minister of Fire
Okay, you did some stuff wrong. Nothing fatal, but these are not habits to be encouraged. I have no professsional training, but here's what I think:
Yeah, that didn't do anything.
That was an excessively bad idea. Carb cleaner will remove the oil film from the engine parts. That oil film is supposed to be there. It's important.
Except for the cleaner that made its way down past the rings and through the transfer ports to clean the protective oil film off of the crank bearings too. Again, spraying carb cleaner into the assembled motor is a very bad idea.
That much is good.
Which means you didn't actually have the L screw set correctly, and this...
...was the wrong way to fix it.
I think you adjusted the L screw too lean, so the saw couldn't get enough fuel to accelerate well. Then you compensated for that by setting the H screw too rich, which helps with the acceleration but reduces power and increases the tendency to flood (hard starting).
Try putting the carb back to factory settings. Start the saw. Turn the idle speed up until the chain starts to move a bit. Back the L screw out SLOWLY until the motor starts to run kinda rough. Then start SLOWLY turning the L screw in to lean it out, counting the turns (or fractions of a turn) until the saw starts to die for lack of fuel. The chain will probably pick up some speed before that happens. Now back the screw out again until it's halfway between those extremes. Check the throttle response. If it bogs down, tweak the L screw (NOT THE H SCREW!) until it accelerates well. Generally if it bogs down like you described it doing, you're a little too lean so you need to back the L screw out a bit. If it accelerates well at first but then starts to run poorly if you leave it idling for a while then it's probably a bit too rich.
Once the L screw is adjusted, back the idle speed screw out until the chain stops moving when the saw is idling.
Only after you've got the L screw adjusted so that the saw both idles and accelerates well should you mess with the H screw. The H screw controls the mixture when the saw is running wide open, not how it accelerates or idles.
Yeah, that didn't do anything.
That was an excessively bad idea. Carb cleaner will remove the oil film from the engine parts. That oil film is supposed to be there. It's important.
Except for the cleaner that made its way down past the rings and through the transfer ports to clean the protective oil film off of the crank bearings too. Again, spraying carb cleaner into the assembled motor is a very bad idea.
That much is good.
Which means you didn't actually have the L screw set correctly, and this...
...was the wrong way to fix it.
I think you adjusted the L screw too lean, so the saw couldn't get enough fuel to accelerate well. Then you compensated for that by setting the H screw too rich, which helps with the acceleration but reduces power and increases the tendency to flood (hard starting).
Try putting the carb back to factory settings. Start the saw. Turn the idle speed up until the chain starts to move a bit. Back the L screw out SLOWLY until the motor starts to run kinda rough. Then start SLOWLY turning the L screw in to lean it out, counting the turns (or fractions of a turn) until the saw starts to die for lack of fuel. The chain will probably pick up some speed before that happens. Now back the screw out again until it's halfway between those extremes. Check the throttle response. If it bogs down, tweak the L screw (NOT THE H SCREW!) until it accelerates well. Generally if it bogs down like you described it doing, you're a little too lean so you need to back the L screw out a bit. If it accelerates well at first but then starts to run poorly if you leave it idling for a while then it's probably a bit too rich.
Once the L screw is adjusted, back the idle speed screw out until the chain stops moving when the saw is idling.
Only after you've got the L screw adjusted so that the saw both idles and accelerates well should you mess with the H screw. The H screw controls the mixture when the saw is running wide open, not how it accelerates or idles.
Ok so the you tube vid's were wrong then, lol. As for the carb cleaner yes it removes the protective oil, but pouring some fuel/oil mix in and letting it sit for a while puts some of that back pouring that out and putting things together helps. Granted no it's not the best practice. Also attempting to start motor several times to get new fuel through the system and letting that soak in for a few days was something else I did. I cleaned the saw as described a week ago, poured some fuel/oil mix into motor let that sit for about an hour I think I was cleaning the crud and saw dust of the bar while it sat and cutting I think two rolls of worn out duct tape off of the handle. After it was cleaned put together with new filter and plug I attempted to start it full choke till it flooded (I got it to kick over a few times it would cut off after 2 seconds, goal was to get fuel/oil into the system then leave it alone to let it soak in and lube everything). I've been told but haven't tried that cleaning the cylinder then spraying white lithium grease into it is also helpful but. You say what I did was wrong so lesson learned. The way I have been adjusting the carb is how I was shown not just by watching you tube vids but by two old heads that worked in logging with my dad. But I will try things your way tomorrow (after new fuel filter and atleast taking carb apart to clean it. Carb kits normally have to be ordered and take a while to arrive).
I wouldn't use white lithium grease in the cyl. "First" time lube can be a little 2 stroke oil or Marvel Mystery Oil. You have fuel delivery problems - monkeying with cyl/piston isn't going to change that. Your carb needs attn. Screen could be full of debris and varnished. Fuel pump diaphragm could be hard. Metering diaphragm could be hard. Internal ports could be varnished/plugged. Needle lever could be out of adjustment but I'd bet unlikely.
Jon1270
Minister of Fire
White lithium grease!? Wow. Keep in mind that any lubricant used inside a 2-stroke motor ultimately finds its way into the combustion chamber. If it doesn't burn cleanly then it will leave residue on the piston, cylinder, spark plug, muffler screen... not exactly what you're going for if you're trying to clean things up. Lithium grease is not designed to burn.
What were you trying to clean out of the motor anyhow? When saws are left to sit unused for a while, there isn't generally anything inside the motor that would be problematic. Fuel systems definitely degrade if left for long periods with fuel in them, but so long as the machine is kept reasonably dry the inside of the engine is usually fine.
As to the tuning, some aspects of what you did that were right. The L screw does get adjusted before the H. I don't know what the youtube videos and the old timers you talked to said, but the problem with what you described having done is that you were using the H screw to correct acceleration problems, which is definitely not its job.
You mentioned having checked the fuel line, but did you take a look at the impulse line too? I don't think it's all that likely to be the problem, but it's worth checking.
The duct tape on the handle is a little worrisome, because it makes me wonder about the overall condition of the saw. Was the original black plastic handle covering still there under the tape? If the saw has been used so much that the plastic covering actually fell off and needed to be replaced then, well, that would be an extremely heavily used 028. It's an older model, but not that old. Shouldn't really be an issue if the compression is good, but I don't know how you're testing that. Can you pick the saw up by the starter handle without the full length of the rope immediately pulling out?
It's worth mentioning, too, that a serious air leak can make it impossible to get a saw running properly even if the carb is clean, no matter how the screws are adjusted. I wouldn't be too worried about that yet because other explanations are more likely, but it is good to be aware of.
Once you get it running and accelerating well, you'll still need to adjust the H screw. It's probably best to discuss that separately, but it's a very important adjustment too.
What were you trying to clean out of the motor anyhow? When saws are left to sit unused for a while, there isn't generally anything inside the motor that would be problematic. Fuel systems definitely degrade if left for long periods with fuel in them, but so long as the machine is kept reasonably dry the inside of the engine is usually fine.
As to the tuning, some aspects of what you did that were right. The L screw does get adjusted before the H. I don't know what the youtube videos and the old timers you talked to said, but the problem with what you described having done is that you were using the H screw to correct acceleration problems, which is definitely not its job.
You mentioned having checked the fuel line, but did you take a look at the impulse line too? I don't think it's all that likely to be the problem, but it's worth checking.
The duct tape on the handle is a little worrisome, because it makes me wonder about the overall condition of the saw. Was the original black plastic handle covering still there under the tape? If the saw has been used so much that the plastic covering actually fell off and needed to be replaced then, well, that would be an extremely heavily used 028. It's an older model, but not that old. Shouldn't really be an issue if the compression is good, but I don't know how you're testing that. Can you pick the saw up by the starter handle without the full length of the rope immediately pulling out?
It's worth mentioning, too, that a serious air leak can make it impossible to get a saw running properly even if the carb is clean, no matter how the screws are adjusted. I wouldn't be too worried about that yet because other explanations are more likely, but it is good to be aware of.
Once you get it running and accelerating well, you'll still need to adjust the H screw. It's probably best to discuss that separately, but it's a very important adjustment too.
Just a note: if ( more than likely though) the unit was fueled with Ethanol fuel the carb passages themselves could be corroded - even a rebuild will not correct that condition. If its not too bad it is possible to dial it out. In some cases though the jets get etched badly.
The previous owner of the saw owns a mansion, bought the saw brand new and only cut maybe a cord of wood a year or two if that (when he felt like doing something manly instead of buying the precut bundles they have outside of the grocery store, his exact words) to use in his out door fireplace. He would use it, put it up, repeat if the saw wouldn't cut he would go buy a new chain he never bothered with sharpening them. The saw still had original stickers on it considering it's age and the amount of gummed up oil and sawdust that was on it. I literally washed all the plastics in the kitchen sink with dawn dish liquid and the saw looks almost new. This saw spent more time in the shed than in actual use from what I was told. It came with a black metal handle no rubber gripper on it. His solution was to wrap black duct/electrical tape on it several times for purchase. The black paint was still there under the tape except for on the very top it had worn through.
I found the problem when I removed the carb. Fuel line and impulse line are good no cracks or defects as far as I can tell. I found the problem though, carb diaphragms were deteriorated horribly, screen was gunked and varnished. Got a new fuel filter today, asked about a rebuild kit and they wanted 35.00 I got the fuel filter but said no to the kit. They are at most 15.00 online because I rebuilt a homelite super xl carb before and the one in my dads stihl (idk the model it's bigger than this wb 36 inch bar i think and he used it for 7 years working in logging. well it was one of the last ones he used). Going to call two other local suppliers if they don't have one at a reasonable price I'll just order the one off line. Its a tillotson carb, and I know most of the places I've tried here have zama and walbro but one place I've never tried before I'm hoping may have what I need. Currently have all the parts to the carb in container full of carb cleaner to soak and break up the varnish. Also I agree that white lithium grease sounded like a bad idea since it was thicker than what would normally run through the cylinder but figured I'd throw it out there and see if anyone had tried it. And when I was taught how to work on two-cycle engines spraying carb cleaner through the cylinder to blast out debri or any build up was what I was taught, including how to tune a carb. It's worked so far for me so that's why I kept doing it. Aside from what I've seen on youtube (and I've watched hundreds of vids of ppl doing the wrong stuff and ppl that seemed to know what they were talking about) I haven't had many avenues to ask someone about how to work on them. I have what the old timers taught me, some trial and error knowledge, little bit of you tube thrown in there. Any way I've learned some new stuff and if anything else pops up I'll run it through here.
Yes I can pick it up by the rip cord about a foot off the floor before the saw starts to move and the weight of the saw pulls it down slowly.
Marvel Mystery Oil is probably my favorite oil to use aside from CLP or M-Pro 7 gun oil. A side note I actually use M-Pro 7 gun cleaner on my tools when I'm done seems to cut the grease and gunk right off wipe them off with a rag toss back in tool box. Both oils and gun cleaner cuts right through rust when I'm restoring old tools.
I found the problem when I removed the carb. Fuel line and impulse line are good no cracks or defects as far as I can tell. I found the problem though, carb diaphragms were deteriorated horribly, screen was gunked and varnished. Got a new fuel filter today, asked about a rebuild kit and they wanted 35.00 I got the fuel filter but said no to the kit. They are at most 15.00 online because I rebuilt a homelite super xl carb before and the one in my dads stihl (idk the model it's bigger than this wb 36 inch bar i think and he used it for 7 years working in logging. well it was one of the last ones he used). Going to call two other local suppliers if they don't have one at a reasonable price I'll just order the one off line. Its a tillotson carb, and I know most of the places I've tried here have zama and walbro but one place I've never tried before I'm hoping may have what I need. Currently have all the parts to the carb in container full of carb cleaner to soak and break up the varnish. Also I agree that white lithium grease sounded like a bad idea since it was thicker than what would normally run through the cylinder but figured I'd throw it out there and see if anyone had tried it. And when I was taught how to work on two-cycle engines spraying carb cleaner through the cylinder to blast out debri or any build up was what I was taught, including how to tune a carb. It's worked so far for me so that's why I kept doing it. Aside from what I've seen on youtube (and I've watched hundreds of vids of ppl doing the wrong stuff and ppl that seemed to know what they were talking about) I haven't had many avenues to ask someone about how to work on them. I have what the old timers taught me, some trial and error knowledge, little bit of you tube thrown in there. Any way I've learned some new stuff and if anything else pops up I'll run it through here.
Yes I can pick it up by the rip cord about a foot off the floor before the saw starts to move and the weight of the saw pulls it down slowly.
Marvel Mystery Oil is probably my favorite oil to use aside from CLP or M-Pro 7 gun oil. A side note I actually use M-Pro 7 gun cleaner on my tools when I'm done seems to cut the grease and gunk right off wipe them off with a rag toss back in tool box. Both oils and gun cleaner cuts right through rust when I'm restoring old tools.
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Jon1270
Minister of Fire
Wow, that looks like a very early 028, and you're right that the plastic is in great condition for its age. Sounds like the carb rebuild will get it going easily. Let us know how it goes.
You should find a new shop. Rebuild kits for the tilly are maybe $10-$12. Check eBay if you havent found one already. I dont like to soak chainsaw carbs, as some of them can have plastic internal check valves that can get eaten with carb cleaner over a long period.
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