Stihl Carb tuning

[golfandwoodnut]

My Stihl 390 is in need of a little tune up. It had two problems, one is that it would stall when cold and the other is that when I am cutting full bore on a log sometimes it will bog down and I have to ease off then go again. I fixed the stall by just turning the idle up a little. I am wondering on the other problem if I should just open it up a quarter turn for more fuel or what do you guys recommend?

 

[ANeat]

The first things I do if the saw, or any other "engine" like that acts like it is going out of tune is make sure I have fresh gas (gas/oil of course), check the air filter, and check the spark plug. (probably the fuel filter as well on the Stihl)

Now if all that is good try a 1/4 or half turn, just keep track of where you are on your "turns" if you need to get back to the original point

 

[smokinj]

My Stihl 390 is in need of a little tune up. It had two problems, one is that it would stall when cold and the other is that when I am cutting full bore on a log sometimes it will bog down and I have to ease off then go again. I fixed the stall by just turning the idle up a little. I am wondering on the other problem if I should just open it up a quarter turn for more fuel or what do you guys recommend?

Make sure the air filter is clean. Then adjust as need will post info on that afterwhile.

 

[golfandwoodnut]

I did blow out the air filter with my air compressor about a week ago, so I do not think that is the issue.

 

[SWNH]

My Stihl 390 is in need of a little tune up. It had two problems, one is that it would stall when cold and the other is that when I am cutting full bore on a log sometimes it will bog down and I have to ease off then go again. I fixed the stall by just turning the idle up a little. I am wondering on the other problem if I should just open it up a quarter turn for more fuel or what do you guys recommend?

Been there, done that....carb adjustment fixed it. I had the SAME issues. Here's what I found (and did):

http://www.ehow.com/how_5022893_tune-chainsaw-carburetor.html

 

[golfandwoodnut]

It sounds like the H is for high altitude. We are at 1,400 ft but I doubt that would need adjusted. It sounds like I may need to open the L adjustment. Does that sound right? I can always go back so I guess I can give that a try.

 

[fjord]

My Stihl 390 is in need of a little tune up. It had two problems, one is that it would stall when cold and the other is that when I am cutting full bore on a log sometimes it will bog down and I have to ease off then go again. I fixed the stall by just turning the idle up a little. I am wondering on the other problem if I should just open it up a quarter turn for more fuel or what do you guys recommend?

Been there, done that....carb adjustment fixed it. I had the SAME issues. Here's what I found (and did):

http://www.ehow.com/how_5022893_tune-chainsaw-carburetor.html

Nice and simple. Good explanation if it hasn't been done before.

Also try MADSEN'S site for a sound clip of adjusting the 3 screws and more detailed directions. Some newer smaller saws have limiters on the adjusting screws...."for your protection". They can be removed.

 

[smokinj]

here it is!
http://web.archive.org/web/20051018212959/www.madsens1.com/sawtune.htm

 

[golfandwoodnut]

thanks guys I will see what I can do. Jay, I noticed the second WAV sound does not work, it would be nice to hear the reved up sound.

 

[ROBERT F]

I did blow out the air filter with my air compressor about a week ago, so I do not think that is the issue.

I recommend against using high pressure air to "blow out" air filters. The air stream can rip the fibers apart, alowing larger than intended particles to pass thru the filter. If you wanna blow the filters out the air in a can is a safer way to go. just my 2 cents.

 

[jharkin]

Been there, done that....carb adjustment fixed it. I had the SAME issues. Here's what I found (and did):

http://www.ehow.com/how_5022893_tune-chainsaw-carburetor.html

I don't own a Still... But that article is just telling you to crank both high and low speed needles fully lean. That is NOT necessarily correct.

Carb tuning is dependent on your local climate, altitude, etc. If a carb was factory tuned in Denver it wont run right at those settings in Seattle. You cant just set the screws at a spot that worked for somebody else someplace else. This is true for all small engines.

 

[golfandwoodnut]

I was reading in another thread where someone swore by Seafoam. I happened to be at tractor supply last week and bought a bottle. I put a little in the gas tank and I must say it made quite a difference with no carb adjustments. I even cut a log that was about 35 inches in diameter and it went right thru. I do not know if anyone else knows but there is no specific instructions on how much to put in your tank, supply, etc. Does anyone else use this? It does seem to work on cleaning the carb.

 

[HittinSteel]

Sounds like you need to be a little richer (counterclockwise) on both the L and the H. Remember, slight adjustments can make big differences......... a little at a time until shes responding like she should.

 

[ROBERT F]

I was reading in another thread where someone swore by Seafoam. I happened to be at tractor supply last week and bought a bottle. I put a little in the gas tank and I must say it made quite a difference with no carb adjustments. I even cut a log that was about 35 inches in diameter and it went right thru. I do not know if anyone else knows but there is no specific instructions on how much to put in your tank, supply, etc. Does anyone else use this? It does seem to work on cleaning the carb.

I have dumped an entire large bottle in with 1 gallon of gas, mixed the gallon at 40:1, and ran it in a saw, weed eater, and post hole auger that sat in storage for 2 years with gas in them. was the fastest way to clean them up I could come up with. all three are still running after much use.