Stihl 048 stops while idling

[martin p]

Got my old 048 out today to ring up a big ash trunk and found that it peters out when left to idle.

Was ok when last used a few months ago,stored without fuel and filled up fresh today.

Anyone got any suggestions as to cause?

[bmp01]

Spiders built multiple cobwebs over the air filter and blocked it. 

Edited February 22, 2021 by bmp01

[bmp01]

Or as it 'peters out' at idle  then a fuel issue.

Most likely fuel residue left behind as last fuel droplets evaporated out of the recesses and crevaces of the carb. Alternatively, it could be the rubber parts inside the carb have just got to the point they need a refresh.

Worth winding the low speed screw all the way in (gently) and back out to the same point as a quick and dirty test to see if it improves plus you get to know how far off std settings you are.

If it runs ok at speed give it a tentative run, might clear cobwebs out. But be wary of fuelling issues at high speed for fear of seizing it if fueling is wrong.

 

How fresh was the fuel before it went in the can?

[martin p]

10 hours ago, bmp01 said:

Or as it 'peters out' at idle  then a fuel issue.

Most likely fuel residue left behind as last fuel droplets evaporated out of the recesses and crevaces of the carb. Alternatively, it could be the rubber parts inside the carb have just got to the point they need a refresh.

Worth winding the low speed screw all the way in (gently) and back out to the same point as a quick and dirty test to see if it improves plus you get to know how far off std settings you are.

If it runs ok at speed give it a tentative run, might clear cobwebs out. But be wary of fuelling issues at high speed for fear of seizing it if fueling is wrong.

 

How fresh was the fuel before it went in the can?

Thanks , Managed to get a spare half hour tonight and put the carb adjustment screws back to initial settings ie 1 turn anticlockwise and tweaked the L screw to a nice idle and smooth pickup.

will  reset the H screw with a tacho tomorrow.

[bmp01]

13 hours ago, martin p said:

Thanks , Managed to get a spare half hour tonight and put the carb adjustment screws back to initial settings ie 1 turn anticlockwise and tweaked the L screw to a nice idle and smooth pickup.

will  reset the H screw with a tacho tomorrow.

 Nice one, glad you got a result.