Total greenhorn struggling w/ every saw i own, please help....??!!!

[AMATEURsawboy]

i'm fairly new 2 chainsaws but i want 2 fix a chainsaw that i picked up dead from a buddy, it is a stihl 017, it had a bad carberator so i replaced it w/ the carb off of a stihl 021, which has the hi /lo adjustment screws as well as the idle adjust. it fires right up w/ the choke in full open position but when i switch to half choke or gun the throttle, it dies. when it fires up on full choke, if i feather the switch towards half choke i can get the saw 2 reach full throttle but once i let the switch engage in the run position it dies out.......i've removed, inspected and reinstalled the fuel pickup line and it looked fine. i've set the hi n' lo screws to the recommended default positions ( 1 full turn counterclockwise from seated) and the idle adjust is set about 2 full turns counterclockwise from seated...i'm using freshly mixed 92 octane fuel w/ stihl mix. the little rubber cork/valve thing in the top of the gas tank seems to be as it should.....do i need 2 set the hi n' lo /idle adjustments differently or......??? any help/insight would be VERY MUCH appreciated. thnx =]

 

[blsnelling]

Did you go through the replacement carb?

 

[lentil]

Did you go through the replacement carb?

I would agree, can't just stick it on and expect it to work (unless it's new??) Would definitely pull apart and check diaphragms, needle etc.

 

[Ambull]

I usually raise the idle screw way up at first to keep the saw running. Once I get the carb set a little closer I back it off.

Sounds like your saw is running too lean, or doesn't have enough idle.

 

[00 steve]

Sounds lean. Any time something will only run on choke it is too lean. It wont tach up because when you open that throttle plate it is getting more air but not enough fuel. Start with agood carb rebuild and go from there.

 

[JDNicol]

Did you relocate the impulse passage opening and block up the original?

What about reconfiguring the throttle linkage (shouldn't cause the problems you are describing but still needs to be done to enable the throttle plate to open fully).

 

[C SAW 090]

saw help

I picked up a chainsaw manual put out by intertec. it has a lot of diffrent saws and is very detailed and descriptive, it also has the specs of all the saws. Its been quite helpfull to me over the years. I think they have printed a few editions ,you can find them if you search the web a little. How many saws do you have currently?

 

[AMATEURsawboy]

the carb came off my stihl 021 that had less than 50 hrs on it so i'm confident that it's in proper working order. also i forgot 2 mention that after i fire it up a time or 2, i can hear an intermittent hiss noise , from the gas can relief port sucking in air..... i'm assuming that's normal right? cuz it's equalizing pressure in the tank , yea? =]

 

[AMATEURsawboy]

what/where's the impulse opening...??? =]

 

[ncfarmboy]

There are 2 small holes on the back of carb on the cyl side. One has a brass plug (center bottom) the other one is open. These are impulse holes. Remove brass plug this will line up the impulse passage for your 017. You need to plug the other one. JB weld works good. Here is a thread that details the carb upgrade. http://www.arboristsite.com/chainsaw/74899.htm
Shep

 

[Chris-PA]

There are 2 small holes on the back of carb on the cyl side. One has a brass plug (center bottom) the other one is open. These are impulse holes. Remove brass plug this will line up the impulse passage for your 017. You need to plug the other one. JB weld works good. Here is a thread that details the carb upgrade. http://www.arboristsite.com/chainsaw/74899.htm
Shep

Don't know those saws at all, but if he didn't have impulse it wouldn't run at all - there'd be no fuel pumping.

 

[Log Splitter]

Don't know those saws at all, but if he didn't have impulse it wouldn't run at all - there'd be no fuel pumping.

His symptoms are the same as I had on my 361 after I forgot to plug the impulse line onto the new tank/handle. Sure sounds like a missing impulse to me.....

 

[Chris-PA]

His symptoms are the same as I had on my 361 after I forgot to plug the impulse line onto the new tank/handle. Sure sounds like a missing impulse to me.....

Weird. Maybe the choke's enough to pull fuel from the tank without any pump?

 

[Johny Utah]

i'm fairly new 2 chainsaws but i want 2 fix a chainsaw that i picked up dead from a buddy, it is a stihl 017, it had a bad carberator so i replaced it w/ the carb off of a stihl 021, which has the hi /lo adjustment screws as well as the idle adjust. it fires right up w/ the choke in full open position but when i switch to half choke or gun the throttle, it dies. when it fires up on full choke, if i feather the switch towards half choke i can get the saw 2 reach full throttle but once i let the switch engage in the run position it dies out.......i've removed, inspected and reinstalled the fuel pickup line and it looked fine. i've set the hi n' lo screws to the recommended default positions ( 1 full turn counterclockwise from seated) and the idle adjust is set about 2 full turns counterclockwise from seated...i'm using freshly mixed 92 octane fuel w/ stihl mix. the little rubber cork/valve thing in the top of the gas tank seems to be as it should.....do i need 2 set the hi n' lo /idle adjustments differently or......??? any help/insight would be VERY MUCH appreciated. thnx =]

It is 100 percent your carb is dirty. If the engine runs with choke you are getting fuel to the carb it just isn't getting through the other circuits. Those small carbs have tiny orifices in them and it doesn't take much to plug them. The only other thing it could be is an air leak somewhere. When it runs with the choke it compensates for the lean condition the air leak is causing. Before you take the carb apart give it a pressure test. If that turns out ok then you have an air leak in the engine.

 

[AMATEURsawboy]

There are 2 small holes on the back of carb on the cyl side. One has a brass plug (center bottom) the other one is open. These are impulse holes. Remove brass plug this will line up the impulse passage for your 017. You need to plug the other one. JB weld works good. Here is a thread that details the carb upgrade. http://www.arboristsite.com/chainsaw/74899.htm
Shep

i'm willing 2 try that but would first like 2 ask, no disrespect intended, more just for my own knowledge for future reference, why might i need 2 swap which port is plugged ..?? is it because i'm using a carb off of a different saw or...???? =]

 

[Log Splitter]

i'm willing 2 try that but would first like 2 ask, no disrespect intended, more just for my own knowledge for future reference, why might i need 2 swap which port is plugged ..?? is it because i'm using a carb off of a different saw or...???? =]

The port that corresponds to the opening that the impulse line plugs into is the one that should be open.

You can verify that the port plug needs to be swapped by looking for the corresponding opening where the carb mates with the handle. On the other side of that opening will be the impulse line which is needed to pump fuel.

 

[JDNicol]

Impulse inlets circled. 017 type carb on right, 021 type carb on left.

 

[AMATEURsawboy]

whoa! much appreciate the detailed pics. cheers =] so how do i go about lining up the impulse port of the 021 carb if the 017 impulse opening is far left of it... would it be wiser to just buy a new 017 carb or will there be any kind of added "oomph" if i use the modded carb ( assuming i can get it 2 work by modding the carb....)..?? =]

 

[a. palmer jr.]

i'm willing 2 try that but would first like 2 ask, no disrespect intended, more just for my own knowledge for future reference, why might i need 2 swap which port is plugged ..?? is it because i'm using a carb off of a different saw or...???? =]

It sounds like the port in the carb you had is not in the same place as the new one, so you have to use a different port in the flange.

 

[a. palmer jr.]

whoa! much appreciate the detailed pics. cheers =] so how do i go about lining up the impulse port of the 021 carb if the 017 impulse opening is far left of it... would it be wiser to just buy a new 017 carb or will there be any kind of added "oomph" if i use the modded carb ( assuming i can get it 2 work by modding the carb....)..?? =]

It's not good to start modifying chainsaws before you get the basics down first. Put the correct parts on it until you have enough experience to know what might work and what won't. Just my opinion, many would rather not hear it, including my wife..