Stihl 026 Pro - won't start

[Roy Najecki]

I have a Stihl 026 Pro that won’t start. I have owned this chainsaw since 1998. Two days ago it ran out of gas while running, but wouldn’t start after I refilled the gas tank. I’ve read some threads on starting problems with a 026 and have done the following. I replaced the spark plug, and checked the spark – all is okay. I removed the Walbro WT-426 carb and cleaned all ports with spray carb cleaner, including the H / L ports with screws removed. The inlet screen had a coating of brown gel-like substance which I cleaned away. In hindsight, perhaps that’s why the saw ran a bit sluggish recently. The engine runs for a few seconds if I put a small amount of gas/oil mix in the carb throat. The engine isn’t grounding out – I’m watching the little brass bar that it doesn’t touch the spring. The carb membranes and gaskets are clean and in good shape. The float needle looks good and I wiped it clean. The fuel line is intact and clear, and filter is clean. The piston cylinder is not scored. I examined the impulse hose and it looks okay – if there is a crack in it, I can’t see it.

I tried putting a little oil in the impulse hose to see if it got sucked in/out when I pull the cord. I couldn’t tell as the oil seemed to just flow down the hose. I did attach a vacuum gauge to the hose and pulled the cord. The vacuum gauge needle jumped a little, but in the direction it would go if the impulse hose was pushing air out. I then attached a vacuum pump to the impulse hose to see if would hold a vacuum. It didn’t hold any vacuum. I tried this with the piston all the way down, part way down, all the way up, etc... Since the piston rings aren’t below the level of the carb throat hole I really didn’t expect to see a vacuum created anyway.

I reassembled the carb and tried to start the saw. No luck. But as before, with a little gas/oil mix poured down the carb throat it does run for a few seconds. I pulled the carb out again, removed the metering chamber cover and gas is in the chamber. The spark plug is dry.

So I’m thinking either the carb is bad, or there is a crack in the impulse hose I can’t see. But if the impulse hose was bad, fuel shouldn’t be getting to the metering chamber – right? Since it might take a while to disassemble the saw handle from the crankcase I don’t want to do it unless the impulse hose is the likely problem. (I have never taken a saw apart before.) Assuming it’s not the hose, is my choice then either a new carb, which would be a WT-194 ($45) or try the K20-WAT carb kit ($15)? Or should I disassemble the handle/crankcase and check the impulse hose? BTW – the parts manual says I should have a WT-403A carb on the 026 Pro, but my carb is marked WT-426.

Your thoughts?

 

[2000ssm6]

Sounds like the carb won't flow fuel. Try the 194.

The impulse needs to be tested by applying pressure to one end and plugging the other. Submerge the hose in water and apply a light amount of pressure. If you see bubbles, there is your leak.

Have you checked the fuel line and fuel filter to make sure the line is good and the filter is clean? Do the fuel line the same way as above.

 

[blsnelling]

Sounds EXACTLY like the 025 I've been working on.

 

[scootr]

Souds like you might have some of that brown goo in the primary circuit of your carb. Did you place the plastic tube of your carb cleaner against the small holes in the venturi? They are very small, that is where your fuel should come when trying to start it. If you place the tube in all the small holes in the carb, you should see carb cleaner coming out of the small holes and the main jet. I would clean her out again. A quick way to check the impulse hose, place a dab of grease on the end, should suck it in.

 

[andrethegiant70]

Souds like you might have some of that brown goo in the primary circuit of your carb. Did you place the plastic tube of your carb cleaner against the small holes in the venturi? They are very small, that is where your fuel should come when trying to start it. If you place the tube in all the small holes in the carb, you should see carb cleaner coming out of the small holes and the main jet. I would clean her out again. A quick way to check the impulse hose, place a dab of grease on the end, should suck it in.

+1 Carb is plugged or impulse went inop. It is interesting to note that the saw was running until it RAN OUT OF GAS. I'd be looking in your gas tank and inspecting your fuel filter. Are you sure it's still attached? You may have sucked some debris. If it is still attached, I'd remove it and blow into it to see if its time for a new one.

I have a Jonsereds 910 that was running ratty at idle and I had recently rebuilt the carb. At my wits end, I yanked the needles on it and there it was, a gout of crud.

I would uninstall the carb, take it apart, and spritz carb cleaner through all the passages. Wear glasses and grubbies, you never know where the stuff is going to squirt out.

Keep us posted! When the problem saws finally get fixed these are BIG wins! Lots of lessons get learned on these projects.

 

[Roy Najecki]

I did pull the fuel filter and fuel hose, and both are fine and connected. I know fuel runs good through the hose because as I was working on the saw with fuel in the tank, I unintentionally tipped the saw in such a way to start a siphon of the fuel. Gas was spouting from the carb end of the fuel hose like a geyser.

I did take the carb completely apart, except for the welch plug, and while wearing goggles, spritzed carb cleaner with a fine red plastic nozzle, through all the passages. The carb cleaner came out of all the holes that previous posts indicated that it should. I also did it while covering the metering chamber inlets so cleaner came out of the outlet valve and three progression jets.

Sounds like I should do it again, as perhaps I may have just dislodged some crud when I tried to restart the saw. At the same time I'll remove the fuel hose and give it the water test for air holes.

A dab of grease on the open end of the impulse hose sounds like an excellent idea, and I'll try that tonight. If that doesn't work I'll then remove the saw handle so I can remove the impulse hose and give it the water test.

I'll keep you posted.

BTW - I did a price check on the carb kit at my three local dealers. They wanted around $40 for a kit. At that price I can buy a new carb online.

 

[2000ssm6]

I had a 026 that did the same thing. I cleaned the carb several times and got very pizzed, it just would not flow. Got a new carb and sawed away.

 

[andrethegiant70]

BTW - I did a price check on the carb kit at my three local dealers. They wanted around $40 for a kit. At that price I can buy a new carb online.

Ouch, that's just not right. It should be $10 or so. If my dealer quoted me that price, I'd doublecheck everything he said from then on.

 

[Roy Najecki]

This is a follow up to my non-running Stihl 026. After a few weeks of doing other things and waiting for parts to arrive, today I took a few hours to work on the saw. As recommended I checked the fuel and impulse hoses - they were fine with no leaks. If you are going to do this, I recommend you have long needle nose pliers to grasp the impulse hose, and you have to take the handle/gas tank assy off the chainsaw, which is held on by numerous Torx screws - some hidden under rubber/plastic covers. I was surprised that Stihl didn't standardize the screw lengths.

I originally intended to get a new WT-194 carb. I did order it and was told it would be available in a week, however a day later I got a call that it was backordered until who-knows-when. Anyway I rebuilt the original carb with the Stens 615-463 carb kit ($8) which replaces the Walbro K20-WAT kit. I compared the old and new parts and noticed a difference. The inlet control lever, which raises and lowers the inlet needle, had a worn dimple-like spot, not seen on the replacement. Likewise the metering diaphram, which has the bonded rubber/metal parts, had a little wear on the center nipple. The inlet needle looked okay, though the original has a rubber tip, whereas the replacement is all metal. Obviously I replaced the other parts (gaskets, screen, pump diaphram, etc.) supplied in the kit. With the Walbro metering gauge ($6) I checked the height of the inlet control lever, which was perfect (ie just under the carb body surface) right out of the kit. I turned the high/low screws out one full turn.

After a few pulls on the cord the saw started up. I bucked a few limbs and so far so good.

 

[2000ssm6]

Good to see you got her running!

 

[stihl026]

I have the same problem with my stihl 026. I bought the rebuild kit and am ready to go to work. I took off the two nuts holding the carb in place, but I can't figure out how to get the throttle wire unhooked to get the carb out. Can anyone out there walk me through this?

 

[Bowtie]

I have the same problem with my stihl 026. I bought the rebuild kit and am ready to go to work. I took off the two nuts holding the carb in place, but I can't figure out how to get the throttle wire unhooked to get the carb out. Can anyone out there walk me through this?

On the back of the handle, on the bottom is a screw holding the black part of the handle on. take that scre off, and the black part of the handle will lift up and off, then you can take the throttle linkage off.

 

[stihl026]

Thank you

Thank you for the help. The trigger came right out and carb with it.

 

[Bowtie]

Thank you for the help. The trigger came right out and carb with it.

No problem, thats what this site is all about...