Stihl 028 Carb and another problem

[Sagetown]

Generally an old used saw may need nothing more than replacing the fuel and impulse hoses to get it running again.

Go ahead and change out that impulse hose before you go any farther. Use a pair of long needle nose pliers. I believe you've already said you replaced the fuel hose, so you should be good there. Make sure the fuel filter is resting in its proper place in the tank.

Hope you get it going w/o any other problems...

 

[retoid]

Yeah, I called the local shop and they stock the impulse lines. So I'll pick one up after work.
I'm a bit upset at the local shop for handing it back to me saying it ran fine without the bar and chain. But it did not. I called him up again and he mentioned wanting to clean out my carburetor, this would just be useless labor to pay for since it's clean. A bit upsetting/frustrating with how much time I've put into this saw already and still not getting very far. I have this tree taking over my driveway forcing me to park in the mud, gotta get that thing cut! hehe

So recapping over everything, what is most common going to cause the saw to run like that? (vid)

 

[fidiro]

Would fuel quality do that? What about case/crank seals leak if not the impulse line? Air filter clean?

 

[Fish]

Turn your high speed screw ccw a 1/4 turn and start it again like in the vid, see what happens.
Remove the kill wire from the coil and try it too. Has the coil been rubbing the flywheel?

I still think it is ignition related.

 

[retoid]

fidiro, I am thinking gas quality could be an issue as well. I have already emptied out the gas from the tank prior to disassembling it. The saw is generally clean for how old it is, after I bought it and tested it out, it would not start and the gas was leaking. So I took it apart and cleaned as much out as possible with compressed air, including the air filter.

Fish, ok I've got it almost all reassembled, ran short on time last night. Before I adjust the High speed, I'll test it out. There are no signs of the flywheel rubbing, here is a pic that shows that there is a gap between the flywheel and armature.

Thanks for your help so far guys, it's very much appreciated. I'm excited to get this thing running.

I also wanted to mention that I had this saw running fairly well after cleaning it and replacing the fuel line and fuel filter. I hadn't touched anything else.
Threw a new bar and chain on it. It would idle good, and rev good. I tested it out by cutting some tree limbs, it would cut through great but eventually when trying to cut something thicker it would die.
This could have caused by the broken needle bearing. So to say the least it was running fairly well before.

 

[PA Plumber]

The "running for a while and then dying out" sounds like it could be the tank vent.

I believe cleaning the tank vent has been mentioned.
I'd look at it again, pull the tube, remove both screws, clean the threads on the screws, clean the vent tube and reassemble.

 

[retoid]

PA Plumber, good call, that was actually one thing I did not clean. I just inspected it.
I'll pull it tonight and clean it out, thanks.

One difficulty this may cause is I am changing more than one thing at a time before testing it out again so I may not know the actual fix if/when I do get it running.

 

[retoid]

Awesome! I got it running and sounds pretty good.
I'll have to test it in some wood with the bar and chain on.
I cleaned out the tank vent, which was not very dirty and made up a new mix of gas. ! So happy right now.

One problem, the kill wire seems to be slipping out of its sleeve and it doesnt want to kill it all the time.
How exactly does this thing work? whats different in the connection between off and on (no choke)?

 

[fidiro]

Good to hear. Hope it holds up cutting. I would dab a little gasoline proof(or not) silicone on the end of the wire, just a bit to hold it in place.

 

[diggers_dad]

Nice job getting it running. I wish ANY of my saws looked that clean...I'm much better at getting 'em dirty. :msp_biggrin:

 

[PA Plumber]

Maybe just pinch the end of the kill "sleeve" to hold the wire in place?

 

[diggers_dad]

Awesome! I got it running and sounds pretty good.
I'll have to test it in some wood with the bar and chain on.
I cleaned out the tank vent, which was not very dirty and made up a new mix of gas. ! So happy right now.

One problem, the kill wire seems to be slipping out of its sleeve and it doesnt want to kill it all the time.
How exactly does this thing work? whats different in the connection between off and on (no choke)?

To answer your question on the kill switch wire... When you move the switch from "run" to "stop" the metal spring clip (screwed to the metal body of the saw) connects to the wire with the brass end held at the end of the switch. When that connection is made all of your spark goes to the saw body (ground) instead of to the spark plug. That's why Fish wanted to know if it was touching anything. Sometimes the wire that goes back to the ignition will have a bare spot, making the spark weak or dead by "grounding it out".

 

[wkmincey]

You can solder the kill wire back into the sleeve. That's what I did to mine.

 

[retoid]

Thanks, soldering it seems to be the best way to go, retaining connectivity.

Diggers_Dad, Thank you for explaining. I am still a bit confused, main reason I asked was because it seems that when in the Off position it is making connection and while in the On position it is still making connection. Then when on half choke and Full choke it does not make connection.

Off

On

Half Choke

Full Choke

 

[diggers_dad]

You are correct in thinking the switch should NOT make connection in the "run" position, only the "stop" position. It is possible that the spring that attaches to the saw has been bent, changing the two pieces position relative to each other. However, it needs to be an easy move from "run" to "stop" in case you need to shut it off FAST.

If it runs in the "run" position and stops in the "stop" position with a smooth movement, I would leave it alone. If the movement is stiff or you have to fight it to get it to stop, it would be worth it to examine the cause and repair. It's hard to get spare parts for a saw, but near impossible to get spare parts for arms and legs if that thing doesn't shut down when it's supposed to. :msp_cursing:

Be safe. DD

 

[retoid]

haha yeah no kidding.

Thanks for the advice. And good thing for the chain brake

 

[retoid]

Well I spoke to soon.
Today I put the bar and chain on and tested it out. The idle seemed good, the chain was barely moving forward, when I gave it full throttle it died shortly after, then i tried it again and it started recreating that same high rev low rev thing again and eventually died. So I tried removing the bar and chain to test it out again and it continued doing the same thing.
I also tried moving the High speed back (ccw) 1/4 of a turn with no luck, and then tried removing the wire again. Still no luck. It keeps wanting to rev high for a bit then it will eventually slow down and die.
I have 3 videos of each test, I'll just put one on here for now since it's pretty much performing the same throughout all three.

[video=youtube;fFESXGNiy2g]http://www.youtube.com/watch?v=fFESXGNiy2g[/video]

 

[PA Plumber]

I've had out of adjustment carbs do that exact thing.

Just to confirm, you did run the H and L screws all the way in and then back out 1 turn? When the H and L screws are turned in, a gentle touch doesn't hurt.

If the saw is idling very high, I'd consider backing the idle adjustment screw out until it settles down a little. If it will barely run, maybe turn the idle screw in (clockwise) until it will stay running.

Also, running WOT (Wide Open Throttle), without a bar and chair, doesn't seem like a good idea. I've never done it though.

 

[Dan_IN_MN]

When it goes to stall, can you keep it running by applying the choke a bit? IMO if you can keep it running with a bit of choke it's fuel related. If not ignition.

 

[retoid]

Ok so I turned the H and L screws in all the way and started them off at 1 turn out each. I got the saw fired up and idling, it wanted to slowly die after taking off the choke but was idling very high with the choke on. I fired it up again and it stayed idling for a bit without choke, I adjusted the L CW a bit and it wanted to kill it so I adjusted it CCW a bit and it slowly was idling better, at 1 and a 1/4 out it idled best, so i rev'd the engine a bit and it would idle but very high, I backed the idly screw back some, so it would basically idle low for a bit like it should then it would start to idle super high. The idle is not consistent. One adjustment will help but only for a little bit.