My 038 Magnum has a mysterious symptom

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stihldragon

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I got this saw from its first owner, a home owner. It's got low hours and it's been garage kept in it's carrying case. I traded my ms290 and a Toro push mower for it. Wow! Whata deal. It's twice as powerful as my ms290 was. Today when I was cutting a tree with it, as I pointed the saw down, it died. I quickly brought it level and it came back. It's cutting off when you aim it up or down and it came back. What does that symptom mean, intake boot leak?

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Look at intake and impulse.

I've also seen ignition or coil wire routed so it gets pinched, then insulation wears and that will short.

From there fuel line/filter and carb.

Seals are usually leaning left/right.
I thought it acted like a spark fail moreso than an air leak. Thanks for the advice, I'll look for an issue there. I'm supposed to be using it for a big job today.


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I thought it acted like a spark fail moreso than an air leak. Thanks for the advice, I'll look for an issue there. I'm supposed to be using it for a big job today.


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The area between the cylinder and the tank handle is very dirty. I'm going to separate them for cleaning and replace the the intake boot and impulse line while I'm in there. It's a 1980,s model so it needs rubber replacement by now. Plus, It's really soft and week feeling.

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More likely to be fuel pooling in the manifold, carb set too rich on the H screw or the carb is flooding a bit from a stiff metering diaphragm. When I have a saw exhibit these symptoms the carb gets pulled, cleaned and re kitted.

Would that show up just checking the plug, showing rich condition? Besides diaphragm, sounds like needle/seat could be culprit for too rich.

Would not H- rich make it run like a dog anyway and have exhaust carbonized/oiled up?

Just some thoughts.

I have seen the pinched wires on 038s. Either bad routing and/or worn out AV buffers.
 
I got this saw from its first owner, a home owner. It's got low hours and it's been garage kept in it's carrying case. I traded my ms290 and a Toro push mower for it. Wow! Whata deal. It's twice as powerful as my ms290 was. Today when I was cutting a tree with it, as I pointed the saw down, it died. I quickly brought it level and it came back. It's cutting off when you aim it up or down and it came back. What does that symptom mean, intake boot leak?

Sent from my Z557BL using Tapatalk
The cause of the mysterious symptom was the high screw on the carburetor was maladjusted and a quarter turn counter clockwise made it run properly.

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More likely to be fuel pooling in the manifold, carb set too rich on the H screw or the carb is flooding a bit from a stiff metering diaphragm. When I have a saw exhibit these symptoms the carb gets pulled, cleaned and re kitted.

Agreed. Also if the carb was gone through and the metering lever set too low you'll get that exact symptom. Did that once early in my saw career (lol) and it took me a lot of testing and parts swapping to figure it out.
 
Agreed. Also if the carb was gone through and the metering lever set too low you'll get that exact symptom. Did that once early in my saw career (lol) and it took me a lot of testing and parts swapping to figure it out.
I adjusted the H screw just to see what would happen and at first, it seem to be running better. It didn't seem to be too lean. That symptom didn't come on right away. It started later in the day. When I adjusted it back the way I had it, it was cured. Intake, impulse, and coil were fine.

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Harley, in back seat of a 65 Dodge? :thisthreadisworthlesswithoutpictures: :ices_rofl:
The fuel line on my 038 super parts saw is cracked above the filter. I robbed the oiler gears from it to fix the Magnum. I'm ordering parts to rebuild it soon. It's in the black box in the pic
7145bc720172fbd1d12b86d44360143f.jpg


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