KG441c
Keith
Best thing to do at this point is read the service manual and search here on as for oil seals and start reading and u will learn what to do before u jump in and tear up more than fixed
026 Carburetor Rebuild - The Saga Continues
- Thread starter woodeneye
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woodeneye
Hardwood Hunter
Can anyone recommend a pressure and vacuum unit for someone on a budget?
KG441c
Keith
mity vac silverline 8500 is 63$
woodeneye
Hardwood Hunter
Good idea. I just read earlier and I noticed a lot of people have varying opinions on how to remove oil seals. Everything to punch and pry to buying a $200 tool.
KG441c
Keith
The stihl seal remover is best bet but$$$$. With the screwdriver method or screw be careful not to scratch the crank or case bore
KG441c
Keith
Pressure test that thing before u tear seals out. The mity vac unit will come with a plug to seal ur intake boot and blank the exhauat behind muffler off. Tap into impulse line behind carb and pressurize with 7 to 10psi and spray soap solution everywhere it can leak or just submerge it in a tub of water and watch for bubbles. Keep it pressurized the whole time
woodeneye
Hardwood Hunter
Sounds like a plan. Thanks for all the help Keith! What do u use to plug the exhaust?
KG441c
Keith
I learned all this the hard way and reading alot and pestering a couple of the top builders to death !! lol! anytime
woodeneye
Hardwood Hunter
Oh, I see the kit comes with the plug for the boot. Haha sorry.
KG441c
Keith
U can also buy rubber tapered plugs off fleabay in different sizes for different sized intake boots
Brush Ape
The Port Authority
I'm the same way I'll even wipe my butt on my socks if I had too.
KG441c
Keith
Brushape I read the carb manual u posted . Question . If the carb is starving for fuel does that mean the metering lever is too low and how much does the metering lever affect start circuit?
woodeneye
Hardwood Hunter
Raising the metering lever does help increase fuel Keith. That's what I did to my original carb before the rebuild and it helped a bit. I've done this on many a saw. I've got the official Zama "Z" gauge, waiting on the official Walbro "W" gauge. Oh and btw, got that Mityvac kit coming my way. Should be here Friday.
woodeneye
Hardwood Hunter
I then lowered the lever after the rebuild but went a little too far. I think that saw will run with the rebuilt carb provided the metering lever is at the right height. Just recranking seems to be the issue.
KG441c
Keith
woodeneye
Hardwood Hunter
So I have the Mityvac Silverline kit on order. Anything else I should need to pressure check this saw? Small fittings, stops, anything? I wanna be prepared when I get this thing. Thanks guys!
If your in a hurry, you can borrow a brake bleeder vacuum pump from your local auto parts loan a tool program. Auto Zone, Advance and Napa all loan tools around here, you receive your deposit back when you return the tool.
About the crank seal, you can drill a small hole in the seal and then insert a drywall screw and pull it. Stay off the bearing pocket of the crankcase casting and off the crank. Only drill into the seal. When your doing the pressure and vac tests, turn the crank with your fingertips to expose any flat spots.
Carbs are pretty straightforward. Check to make sure you have the gaskets and diaphragms in the correct order because theyre different from the pump side to the metering side. I believe you mentioned Walbro. You can look up your carb here; http://wem.walbro.com/walbro/family.asp Enter the 'WT-' followed by the number that you will find on the side. There have been problems with leaks in the high speed nozzles of all carbs that use internal check valves. Your engine would run with a leaking nozzle check valve it just wouldnt hold a tune. The other possible problem is a leaking inlet needle. The engine would flood over and over.
Sounds like it might be your ignition module. When they go bad they dont have enough voltage to fire under compression. This is a hard problem to diagnose because when grounding the plug to the cylinder you do get a spark. Check to see if the spark you get is blue in color. If its orange or yellow that may be where the problem is. If your using an 'R' plug, you might try a regular non - resistor CJ-6 or related.
About the crank seal, you can drill a small hole in the seal and then insert a drywall screw and pull it. Stay off the bearing pocket of the crankcase casting and off the crank. Only drill into the seal. When your doing the pressure and vac tests, turn the crank with your fingertips to expose any flat spots.
Carbs are pretty straightforward. Check to make sure you have the gaskets and diaphragms in the correct order because theyre different from the pump side to the metering side. I believe you mentioned Walbro. You can look up your carb here; http://wem.walbro.com/walbro/family.asp Enter the 'WT-' followed by the number that you will find on the side. There have been problems with leaks in the high speed nozzles of all carbs that use internal check valves. Your engine would run with a leaking nozzle check valve it just wouldnt hold a tune. The other possible problem is a leaking inlet needle. The engine would flood over and over.
Sounds like it might be your ignition module. When they go bad they dont have enough voltage to fire under compression. This is a hard problem to diagnose because when grounding the plug to the cylinder you do get a spark. Check to see if the spark you get is blue in color. If its orange or yellow that may be where the problem is. If your using an 'R' plug, you might try a regular non - resistor CJ-6 or related.
cedarshark
Addicted to ArboristSite
Here is how I would approach this saw if it were mine.
1) I do not believe your problem is the carb. If the spark plug is not throwing a fat blue spark, I would replace the coil.
2) Your vac tester will not come with a plug to seal the intake hole behind the carb. I use a flat plate with a piece of inner tube behind the plate to seal the intake or a rubber stopper trimmed to fit. Your exhaust port on the cylinder must be sealed as well. This can be done with a piece of inner tube behind the muffler, then tighten the screws. Plug the van gun into the impulse port on the saw frame where the carb impulse line plugs in. Pump the saw down tp approx -7 psi. If the saw does not hold and leaks off before 10-15 seconds have passed, set the vac gun on pressure and pump the saw up to +7-10 psi and dunk the entire saw in a sink or tub of water and watch for bubbles. The bubbles willl most likely indicate the leak point.
3) Regardless of the vac test, I think I would take the saw down to the level of removing the cylinder. This is a relatively easy task mechanically on the 026 and you will learn a lot that will be helpful later. This will also give you the opportunity to closely inspect all rubber lines and boots, you can replace your cylinder gasket . Pull the flywheel and check if you have a broken flywheel key and check the gap between the magnets and coil contacts. At 125 lbs compression, that is runnable but that saw should throw 140-160 stock. You can replace the rings when you have the cylinder off and clean up the piston,check for skirt wear, clean up the cylinder and check for scoring. This will require a ring compressor and a set can be had cheaply($10) from site sponsors and auto parts houses. Remember your clutch is left hand thread.
4) Take advantage of this opportunity make the saw a useful learning experience. They can be frustrating at times but usually good solid diagnostic procedures will lead you to the problem. The 026 is the best training saw out there.
1) I do not believe your problem is the carb. If the spark plug is not throwing a fat blue spark, I would replace the coil.
2) Your vac tester will not come with a plug to seal the intake hole behind the carb. I use a flat plate with a piece of inner tube behind the plate to seal the intake or a rubber stopper trimmed to fit. Your exhaust port on the cylinder must be sealed as well. This can be done with a piece of inner tube behind the muffler, then tighten the screws. Plug the van gun into the impulse port on the saw frame where the carb impulse line plugs in. Pump the saw down tp approx -7 psi. If the saw does not hold and leaks off before 10-15 seconds have passed, set the vac gun on pressure and pump the saw up to +7-10 psi and dunk the entire saw in a sink or tub of water and watch for bubbles. The bubbles willl most likely indicate the leak point.
3) Regardless of the vac test, I think I would take the saw down to the level of removing the cylinder. This is a relatively easy task mechanically on the 026 and you will learn a lot that will be helpful later. This will also give you the opportunity to closely inspect all rubber lines and boots, you can replace your cylinder gasket . Pull the flywheel and check if you have a broken flywheel key and check the gap between the magnets and coil contacts. At 125 lbs compression, that is runnable but that saw should throw 140-160 stock. You can replace the rings when you have the cylinder off and clean up the piston,check for skirt wear, clean up the cylinder and check for scoring. This will require a ring compressor and a set can be had cheaply($10) from site sponsors and auto parts houses. Remember your clutch is left hand thread.
4) Take advantage of this opportunity make the saw a useful learning experience. They can be frustrating at times but usually good solid diagnostic procedures will lead you to the problem. The 026 is the best training saw out there.
woodeneye
Hardwood Hunter
Very good right up and tips. For those of you who haven't followed the "saga" as I call it, I have done all of the above besides the leak down tests and replacing the coil. I was to the point of splitting the case when my original problem, a stiff turning shaft, was solved by taking off the entire brake mechanism and cleaning the clutch side once it was removed. Still, if anyone is having similar problems to what I have described, then the above post definitely applies. Familiarizing yourself with your saw is always a good step and you can get a lot done while it's apart. I wish I had a vac/pressure test unit back whrn I had it at that point, as it looks like I'm going back into this saw. And I agree, 026 is a great learners saw, despite a couple quirks.
watsonr
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After all this churn... did you take the carb apart again to make sure nothing was stuck under the metering lever or seal.... almost sounds like a small piece of something is stuck under there. You replaced the fuel line and filter I assume? I've cleaned hundreds of carbs, sometimes that cleaning just doesn't dislodge everything and a second or third cleaning because of this issue is needed. I've even used a bread tie with the plastic stripped off to clean a passage. DON'T use compressed air.
The metering needle should hold 10psi. Hook that mity vac to the fuel inlet fitting and give it some pressure... under water so you can see if it's leaking or holding
BEFORE you rip the saw apart chasing a seal. If it's leaking under 10psi, you have a bad needle or its dirty... why it's flooding.
Not sure how this went to my saw is flooding, no spark and you have a bad seal. Trying to diagnose more than one thing at a time will make you pull your hair our and cause you to buy parts/tools that you don't need. But.... having the right tool is everything.
At 125, that saw will run but not well... but you did say your tester was off.
The metering needle should hold 10psi. Hook that mity vac to the fuel inlet fitting and give it some pressure... under water so you can see if it's leaking or holding
BEFORE you rip the saw apart chasing a seal. If it's leaking under 10psi, you have a bad needle or its dirty... why it's flooding.
Not sure how this went to my saw is flooding, no spark and you have a bad seal. Trying to diagnose more than one thing at a time will make you pull your hair our and cause you to buy parts/tools that you don't need. But.... having the right tool is everything.
At 125, that saw will run but not well... but you did say your tester was off.
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