026 starts hard and idles worse

[084Amateur]

I recently traded a saw needing some parts and work for a rebuilt 026. I brought it home and it scored the piston in about two hours. The man who rebuilt it said he must have missed something in the rebuild and brought me another 026 he had completed.

The "new" 026 had 260 plastic on the top half and the plastic near the carb was dremeled out so the jets could be adjusted. I'm not worried about beauty...the saw started and ran well. I cut with it for about 2-3 hours and began to have a problem idling and starting hard, as in won't start without lots of throttle.

I attempted to retune the carb starting at one turn out for both h and l, and could not get the saw to idle without the LA screwed in as tight as it will go. Even then, I cannot get the nice loping idle you would expect from a chainsaw. It randomly quits though the rpms seem too high. This is at about 1 1/2 to two turns out on L, and it will kill if in farther. In addition, I have to flick the throttle off of idle or the saw kills. H is a turn or so out. Saw will not start and idle when warmed up without lots of throttle.

I have no idea what to do at this point. Compression is 150psi, but I have neither the tools nor the knowledge to diagnose the problem. Plug is very light tan/off-white. I've got maybe 10 hours on this saw and am ready to throw it across the garage in favor of my 028 super.

Any ideas?

 

[pioneerguy600]

You say the side of the airbox has been dremeled out so the screws can be adjusted, this tells me that the original carb was likely a single screw adjustable carb or that the original carb was replaced with one of the new carbs from China. The carb on the saw right now should be removed and looked at closely to determine if it is sealing well to the intake boot, make sure the spacer ring is in there behind the carb also. I have seen a few replacement carbs that would not sit in the airbox straight and were not sealing to the boot tightly, the airbox needed some extra grinding out just ahead of the adjusting screws.

 

[084Amateur]

There were existing holes, but this have been modified for the existing carb by the looks of it. The builder just agreed to take a look at the saw with me present and let me cut with it a bunch before leaving on Monday. Almost a two hour drive, but at least should be running!

 

[084Amateur]

Update: cut again today. Both screws out 1 1/8. Saw fired up right away. Ran well until 1/3 tank and started acting up. Alternates between racing at idle or killing. Doesn't want to rev without flicking the throttle. When ot does idle, dies when I pick it up or tip it extremely in most directions. He thought it might be the fuel filter/pick up? Filter is at about 60 degree angle and won't lay flatter.

 

[Tpagel]

Sounds like you have an air leak on the saw someplace, maybe carb not sealing as mentioned. Maybe a hole in the fuel or impulse line.
Take the videos of it running erratic and post them up.
If the seals didn't get replaced in the rebuild you need to pressure/vac test the saw



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[Wood Doctor]

I kind of wish you could install another carb and see if it does the same thing. I once had an 028 Super given to me to work on that acted just like your 026 does. I swapped the carb out with one from another 028 Super and the saw with hiccups suddenly ran perfectly.

So, I decided to install the "bad" carb in the one that ran OK before, and it accepted the "bad" carb and ran fine. It's things like this that drive you bonkers. Regardless, I suddenly had two saws that ran fine and did not have to buy any parts. A carb swap was all that was needed. Gasp!