Help me figure out my 026 finicky idle tuning and stalling when turned on side

[Jimbo45]

My other saws, it is quite obvious where the L setting is best....about a 1/4 turn between lean surging, and loading up.  Set in the middle, and done.

With the 026, though, when setting the L jet, I can turn the screw a little more than 1/2 turn between the obviously lean and rich boundaries, and even then, those extremes aren't as definitive as with the other saws.  I settle on a setting near the middle if those points, favoring the rich side, and the idle is usually strong, but sometimes, after some time, acts like it wants to load up, and the idle slows a bit, and sometimes dies.  Also, I notice I can back off the idle speed screw until its not even hitting the throttle arm, and the saw will still idle around 2500 rpm.  And, when I tip this saw with the clutch side down, when idling, it will slow, and sometimes die.  If I tip ut with the starter side down, the idle will speed up, then return to normal.

A little background in the saw;  I got it well used. Piston is a little scored, but cold compression at 152 psi.  Checked all jug and case bolts for tightness, new plug, new crank seals, new intake manifold, rebuild carb, new air filter, new fuel line and filter, new impulse line, fresh no ethanol gas.  New 26RM74 chain, and even a new starter rope.

This saw runs like champ with the 18" bar, and seems to cut faster than my new ms290 and my 028 super.  But, the stalling when tipped on its side is annoying.  I would suspect an air leak, but I think ive covered all the possible suspects as far as an air leak.  Is my carb junk, even though I put a full kit in it?

[sablatnic]

I am thinking, in no specific order, fuel line, pulse line, needle valve in the carburettor, oil seals/crank seals, fuel line connector on carburettor (it can be loose or cracked).

[ZeroJunk]

It could be idling a little rich and mix is pooling up in the bottom of the crankcase so when you turn it on the side it floods a little. As far as idle speed you might also take your finger and push on the throttle shaft to make sure it is actually returning all the way to idle.
I also have had several 026's and the idle adjustment like you say makes it hard to find the sweet spot sometimes.

[Jimbo45]

Ok, thanks for the suggestion.  I will lean out the L a little, and see if the tipping stall is reduced.

[Saw Dr.]

On the 026, impulse lines are known weak points.  If it is not that, it is almost always the flywheel side crank seal.  Those are one of the hardest ones to change, and easiest to damage if done wrong.  You are exhibiting textbook signs of an intermittent air leak.  The carb, intake, & fuel line also have to be right, but my $ is on one of the two I have already mentioned.

[Jimbo45]

On the 026, impulse lines are known weak points.  If it is not that, it is almost always the flywheel side crank seal.  Those are one of the hardest ones to change, and easiest to damage if done wrong.  You are exhibiting textbook signs of an intermittent air leak.  The carb, intake, & fuel line also have to be right, but my $ is on one of the two I have already mentioned.

I know, right? I expected the new crank seals to fix this.  I carefully replaced the crank seals and impulse and fuel lines myself, with OEM parts.  Although the flywheel side seal was a bear, I had no reason to believe it isn't installed correctly.  Only thing I can imagine is a carb problem, but it seems unlikely.  Can a bad carb cause stalls when tipping?  Wish I had another 026 carb around here to try.

[lone wolf]

It sure sounds like a vac leak at the crank seals to me just because they are new don't mean they are not leaking. The fact that the idle changes when turned sideways says something right there. Are you able to do a vac test?

[Jimbo45]

It sure sounds like a vac leak at the crank seals to me just because they are new don't mean they are not leaking. The fact that the idle changes when turned sideways says something right there. Are you able to do a vac test?

Not right now.  But, I guess its time I look into a vac testing setup (hopefully a cheap one, this is just a hobby for me).  Let the research begin.  I agree, it sure seems suggestive of a bad seal....

[Icehouse]

My 026 acted the same way, before I did anything I did a search on the then Arboristsite. I found enough evidence to change the carb first. It worked, if you don't have a walbro wt-194 carb on your saw see if you can find one borrow one or what ever and put on your saw. I won't swear that it will cure your problem but it did mine. I have since fixed 2 other 026's saws the same way. Used to be able to find those 194's pretty cheap but I don't know now. Hope this is of some help, like I said no guarantee but it worked for me.

[lone wolf]

Ok well here is what you can do without a tester. this will tell you if there is a vac leak at the crank seals. Take the flywheel of to get to the crank seal put a good amount of any grease on the seal inner and outer sealing areas so any leah would be stopped including the are where the seal touches the cases. Put it back together try it. If same problem do the other side now take off the clutch etc and do that seal. If this dont help you must vac test it.

[ZeroJunk]

Well, if the carb is indeed closing all the way and you can't get it to idle down then that would suggest that it is getting air somewhere.

But, I never put much stock in the RPM change when turned on it's side always being seals. Fuel can pool up in the bottom of the case and make them do that with no air leak involved.

First thing I would do is make sure the linkage hasn't been bent or whatever and make sure the butterfly is actually closing. If it is and the idle is still too high look for the air leak.