Chain saw question

[Thunder Head]

I have a stihl 251. It has developed a problem. If im cutting at high rpms and suddenly let off the trigger it cuts off. It starts right back up with one or two pulls. Very aggravating when cutting small diameter limbs.
Any ideas?

 

[Ray357]

Carburator. Stihl dealer can take care of that for you.

 

[Dbender]

Carb adjustment, tiny increments. Just use a small flat screwdriver and turn 1/8 a turn in or out. How does it idle?

 

[Ray357]

Carb adjustment, tiny increments. Just use a small flat screwdriver and turn 1/8 a turn in or out. How does it idle?

A carb does not just miraculously get out of adjustment that bad. There is either trash in it or ethanol gum in it.

 

[Dbender]

O.p. if your saw is cranking fine and idling, you are just slightly out of adjustment. Probably a little too lean on the high side.

 

[Thunder Head]

It still cranks fine
Its never idled great until it gets good and warm.

Everything seems the same except for this.

I don't mind taking it to a shop. I have one more session to get moms yard cleaned up. Id like to get it done this weekend.

 

[K80Shooter]

If it has never idled it probably just needs to be turned up a bit as mentioned above.

My main question to you is what type of gas are you running in it?

If you're running regular gas you really need to switch over to ethanol free gas. Yes it cost's a little more but not having to deal with issues like you now have will be well worth it.

 

[NE GA Pappy]

enrich the idle circuit a bit. You may have it a bit lean on the high speed side also.

It isn't hard, but you have to know what to listen for when you make those adjustments.

Having said that, you really can't screw it up permanently unless you run the mixture screws in to far and bugger them up.

 

[Darkhorse]

As previously mentioned it sounds like the idle rpm is too low. The first thing I'd do is get the idle correct and go from there, that might fix the problem or get you close enough to finish the job.
As for gas, I concur with K80Shooter, ditch any regular pump gas and go with ethanol free. I keep a couple of 5 gallon cans filled with fresh ethanol free gas and fuel my mowers, atv, and other 4 cycle motors from these cans. Last couple of years I've used premix fuel for my chainsaws, weedeaters and pole saw. Trufuel, Husqvarna, VP and Stihl are some common brands you will find. This is a purer fuel than gasoline and they claim it doesn't go bad with age. I run a couple of saws including a large Pro Model Husky and I'm well pleased with the product.
I urge anyone to try and learn basic carb adjustment and maintenance of your engines. It will save you a lot of time and expense.

 

[Thunder Head]

I use Non ethanol.

The idle has never really been a problem. Only takes about 30 seconds or so. Then it idels fine.

 

[Eudora]

As previously mentioned it sounds like the idle rpm is too low. The first thing I'd do is get the idle correct and go from there, that might fix the problem or get you close enough to finish the job.
As for gas, I concur with K80Shooter, ditch any regular pump gas and go with ethanol free. I keep a couple of 5 gallon cans filled with fresh ethanol free gas and fuel my mowers, atv, and other 4 cycle motors from these cans. Last couple of years I've used premix fuel for my chainsaws, weedeaters and pole saw. Trufuel, Husqvarna, VP and Stihl are some common brands you will find. This is a purer fuel than gasoline and they claim it doesn't go bad with age. I run a couple of saws including a large Pro Model Husky and I'm well pleased with the product.
I urge anyone to try and learn basic carb adjustment and maintenance of your engines. It will save you a lot of time and expense.

I use a TruFuel can to carry my Stihl mix in the woods with me since it is small, sturdy and easy to pour from. I was having my Stihl blade sharpened at the dealer and he noticed the can and asked if that was what I used because it would void the warranty if not using the Stihl mix? Not saying bad things about TruFuel but thought I would pass that info along. Agree on the non-ethanol. Makes a huge difference in any small engine application

 

[NE GA Pappy]

I was having my Stihl blade sharpened at the dealer and he noticed the can and asked if that was what I used because it would void the warranty if not using the Stihl mix?

this isn't true. Research Magnuson-Moss Warranty Act. If it is require to maintain the warranty, then they must supply it free of charge.

That is why every booklet that comes with the product says use XXXXX or equivalent. All you have to do is prove that it mets the spec called out, and they must warranty the product. If you look on the TruFuel can, I bet it calls out all the manufacturers specs that it meets.[/QUOTE]

 

[Hillbilly stalker]

One of the very first thing I check on a troubled weed eater or chainsaw is the muffler or spark arrestor as they call it. They get stopped up from time to time. Usually they just screw out. I clean them with carburetor cleaner, a wire brush and then I pluck a single wire from the wire brush and open each hole. Sometimes it’s the simple stuff . If they can’t breath right they can’t run right. Free and easy to check.

 

[davel]

I have a stihl 251. It has developed a problem. If im cutting at high rpms and suddenly let off the trigger it cuts off. It starts right back up with one or two pulls. Very aggravating when cutting small diameter limbs.
Any ideas?

Had the same issue...took it to a Stihl dealer and they did a carb adjustment.

 

[j_seph]

Not to stihl a thread but my Stihl chainsaw started last year acting like it was running out of gas. Changed filter, took apart and cleaned carb and still does it.

 

[Eudora]

this isn't true. Research Magnuson-Moss Warranty Act. If it is require to maintain the warranty, then they must supply it free of charge.

That is why every booklet that comes with the product says use XXXXX or equivalent. All you have to do is prove that it mets the spec called out, and they must warranty the product. If you look on the TruFuel can, I bet it calls out all the manufacturers specs that it meets.

[/QUOTE]

Being in the autoparts industry, I am very familiar with the Magnuson-Moss Warranty Act and agree. Just thought I would pass along the info he told me just in case a Stihl dealer brings this up. The dealer actually gave me 8 bottles of the Stihl mix when I purchased the saw. When this runs out, I'll probably go back to my TruFuel. Like I mentioned, the cans make great vessels to tote refills in the woods with 'ya.