026 Stihl surging and bogging.

[pioneerguy600]

Where are you pulling vac from? Can`t see in your vid, is the sparkplug in tight?

 

[Ryan_289]

Where are you pulling vac from? Can`t see in your vid, is the sparkplug in tight?

I bought the carb adapter flange from Stihl. It was the one that just blocked the carb boot. I plugged the impulse line up. I will have to check and see if the spark plug is tight.

I watched some videos last night but never found an example of a good vacuum. only ones that failed. I also did not rotate my flywheel on either test. I may redo both tests tonight and do that and see if it moves.

 

[pioneerguy600]

The test flange is a good tool to own, bit pricey but once owned the cost fades. Both vac and pressure should hold the same value but if your saw is still holding 8 hg then it should not be affected by a leak, saws do not create high hg when running, Stihl says that if a saw holds a vacuum of 5.8 then its is good, I like mine to hold 10 and they will if the seals are in good shape. Saws with decomps almost always leak, I plug those before performing a test to eliminate a false leak.

 

[Ryan_289]

So you think mine is good as far as vac/pressure is concerned? I might replace the impulse line just to be sure its sealing against the carb good. I cleaned the carb before, even though it didnt look dirty.

 

[rupedoggy]

I started cutting the logs down into firewood length it also ran great for a tank.

When you changed tanks it acted up? Well check the fuel for water or contaminates. Mike

 

[pioneerguy600]

So you think mine is good as far as vac/pressure is concerned? I might replace the impulse line just to be sure its sealing against the carb good. I cleaned the carb before, even though it didnt look dirty.

I would say the seals are good enough for a while at least. That is a possibility,the lines do stretch and become loose with age, have had a few in that the line would not stay on the base barb but don`t remember having one too loose on the carb end but always a chance. If the line is too loose the carb won`t get enough low alternating to high signal from the crankcase to pump fuel.

 

[Ryan_289]

When you changed tanks it acted up? Well check the fuel for water or contaminates. Mike

Its not fuel. Brand new fuel, brand new oil, bone dry storage tank, Saw tank is clean.

 

[rd35]

I'm with Wood Doctor on this one...sounds like a carb problem. Hey just for giggles, try running your H and L needles all the way down until they seat (lightly) and then back out to their original settings. I have, on more than one occasion, had an old carburetor give me fits as gunk starts breaking loose in it (even after a cleaning....its really hard to get all the dried gunk out of every nook and cranny) and partially clogging the H and L needles causing an intermittent lean condition at idle (reving or high idle) and at full load (over-reving lean and or falling off of power). By running the needles all the way down you, effectively, push the dirt through the jet ports which clears them so fuel can flow proper. Works more often that one would imagine....definitely worth a try if you haven't already done so. Very easy to do. Only takes a few seconds! If this fixes it then great. If it keeps happening, I would definitely go buy a new carburetor for it...they're cheap!

 

[Ryan_289]

I'm with Wood Doctor on this one...sounds like a carb problem. Hey just for giggles, try running your H and L needles all the way down until they seat (lightly) and then back out to their original settings. I have, on more than one occasion, had an old carburetor give me fits as gunk starts breaking loose in it (even after a cleaning....its really hard to get all the dried gunk out of every nook and cranny) and partially clogging the H and L needles causing an intermittent lean condition at idle (reving or high idle) and at full load (over-reving lean and or falling off of power). By running the needles all the way down you, effectively, push the dirt through the jet ports which clears them so fuel can flow proper. Works more often that one would imagine....definitely worth a try if you haven't already done so. Very easy to do. Only takes a few seconds! If this fixes it then great. If it keeps happening, I would definitely go buy a new carburetor for it...they're cheap!

I will try that. Your description almost exactly matches whats going on right now with erratic idle and lean out at full load. If that doesn't fix it, i may just recarb instead of kit. I can find a new WT-194-1 for $42. I've never run an aftermarket carb, will they be good as well or stick with OEM?

I will run it this weekend, there is a tree down at my lease farm that I can cut up. I never did get to run it after i tightened the clamp on the intake boot, we will see how it does.

 

[Ryan_289]

My carb soak idea might work here also. Remove the carb and soak it submerged in mixed fuel inside an empty jar for about 36 hours with the lid on loosely. Then see if that makes a difference. Many times I have found that it does. Also, be sure that the fuel filer (pickup body) isn't blocked up. Replace that also.

I will do this tonight. It will probably be Sunday before I can use it anyway.

 

[rd35]

I've never run an aftermarket carb, will they be good as well or stick with OEM?

I can only speak about the 5 or 6 cheap aftermarket ones I have purchased and installed. Every single one was adjusted perfect from the factory and worked fine! Not one has come back with a customer complaint. That's my experience up till now.