Hey, i am new to the forum but i was wondering if anyone could help me figure out what's wrong with a Stihl 038 super i have. The saw takes a lot of pulls to start, and when it's running it idles faster than it should if it is idling, and then it will idle way down and die. To start it again you basically have to put it back in the start position so it is starting in a high idle. It is always either running with the chain spinning or basically not wanting to idle, but on the high side it seems to run fine although i haven't really ran it since it wont stay at a steady idle. It seems random and never will stay idling one way or the other for too long. I have tried to tune the carburetor but it still always changes from high idling to not idling. I was wondering if anyone has had this problem or knows what the issue is? I have cleaned the carb two times and tried to tune it quite a bit so i dont think its a carb issue but i guess it could be? Any help is appreciated, thanks.
Stihl 038 Super Idle Issue?
- Thread starter th04
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OH_Varmntr
Burner of stored sunlight
The chokes have a tendency to not work. Here's a decent video explaining how the choke baffle doesn't engage all of the way and cause hard starting issues when the saw is cold.
You said you cleaned the carb, but how long has it been since you've actually rebuilt the carb? If it has been years, the diaphragms are probably a bit stiff and won't pump fuel properly. It needs a rebuild, not just a cleaning.
You said you cleaned the carb, but how long has it been since you've actually rebuilt the carb? If it has been years, the diaphragms are probably a bit stiff and won't pump fuel properly. It needs a rebuild, not just a cleaning.
Ok thanks, ill check that out. I havent rebuilt the carb, i might give that a shot too
If you have the means to do a vacuum/pressure test definitely do that. Sounds like you may have an air leak. I have two 038 mags they both had bad clutch side crank seals when I got them. I believe the reason for this is because of the “hidden” clutch. If you’ve had the clutch cover off you probably know what I mean. My theory is the clutch on these saws (and the 028) run hotter than normal due to being concealed behind a cover. The heat is transferred through the crank and cooks the seal. This is obviously based on my own observations due to both my 038’s needing clutch side seals. And they definitely looked like they had been exposed to heat. Anyway, something to consider. If you pull the clutch off you’ll see right away if the seal is leaking.
Ok, I'll look and see if its visibly leaking. I don't have the stuff to do a vacuum test but I did try just flipping the saw all around and seeing if the idle changed and it didn't but that's probably not the proper way to test for an air leak
Other things to look at are the pulse hose, intake boot, and the carb itself. If the high speed nozzle/check valve is leaking that will cause some funky running issues. As I mentioned previously I own two 038 mags and have worked on several variants. Haven’t seen any intake boot leaks, but have seen bad crank seals and carb issues. I’d be looking hard at both of those but definitely check the pulse hose as well.
Ok, sorry this is a beginner question but is the pulse hose the black line coming up straight from the fuel tank
No it will be coming off a barb on the back of the case below the cylinder to the back of the fuel tank next to the intake boot. Pull the air filter cover off the saw. Look into the space between the tank and cylinder. You’ll see the intake boot and a small piece of hose. That’s the pulse hose.
I think it's fine but I'm totally sure what to look for. Would it be dry and cracked or is it not that obvious. Also the clutch side doesn't look like it's leaking anything
Your gonna have to do some cleaning so you can better see what’s going on. In the first picture I can seek the pulse hose but it’s dirty. The areas to pay attention to is where it slips over the hose barb on either end. In the second picture you need to remove the plate that covers the clutch. To do this you’ll need to remove the small e clip and washer. There will then be a external snap ring that retains a large cup shaped washer that will also need to be removed. There’s five small T27 screws that retain the cover. Remove the gears, clutch drum, and clutch. You’ll need a piston stop or you can use the “rope method” to stop the piston, otherwise you’ll never get the clutch off. One thing you can try is leave the clutch on, start the saw, and spray brake cleaner between the clutch and case. If the engine rpm drops and it dies it’s gonna need crank seals. Always replace both.
Should also add, if any or all of this seems overwhelming you mite wanna consider a visit to your local saw shop.
Ok, no that makes sense. Yeah, I have quite a few saws just don't work on them that much besides the basic maintenance parts. This ones been sitting for about a year since I bought it and I finally decided I should just get it running right
Ok thanks for your help. I'm honestly thinking about just taking the handle off and pulling it apart more so I can clean it properly and just replace anything that's potentially the problem.
