# Stihl 028WB



## RKDOC (Jun 20, 2006)

This chainsaw has 110lbs of compression. The fuel line was broke so I replaced the fuel line. The saw has a Tillotson WU40B carburetor. I have cleaned (spray brake clean, no compressed air). Installed a new kit. The saw will start after several pulls. Will run for a few seconds, but I can not rev it up. It acts like it is not getting enough fuel. The tillotson carb is NLA from Stihl or MWE' The carb is replaced by a Walbro WT 16-1 which is also NLA. I have pressure tested the carb and it shows good. Can anyone give some suggestions that I can do to save this saw? Thanks in advance.


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## Rentahusband (Aug 25, 2008)

Possibly a bad crank seal. If there is a bad seal, it will not have sufficient vacuum to draw fuel.


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## RKDOC (Jun 20, 2006)

Thanks rentahusband. I have got the saw to idle. If I try adjusting the mixture screw with the saw running, it will kill the engine. When I speed the saw up it won't go to full throttle. The saw starts bogging down, when I try to adjust the high mixture screw, it kill, no matter which direction I turn the screw.

The saw leaks a ton of bar oil while trying to start it.


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## 30yearTech (Sep 14, 2006)

If I remember correctly the 028 has a fuel pump pulse hose that goes from the crankcase to the fuel pump cover on the saw. I would check this line as the possible source of an air leak.


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## RKDOC (Jun 20, 2006)

Thanks 30 Year. Is there some way to test the pulse line for a leak? or do I have take take off the covers and visually check it? I put some oil in the end of the pulse line then pulled the rope and oil spit out he line.


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## RKDOC (Jun 20, 2006)

Is there any way to test for a crankcase seal leak with out buying the adapters for each make of engine you work on? Thanks for the help.


I noticed on my first post, the carb number is a HU40B not a WU40B.


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## 30yearTech (Sep 14, 2006)

RKDOC said:


> Thanks 30 Year. Is there some way to test the pulse line for a leak? or do I have take take off the covers and visually check it? I put some oil in the end of the pulse line then pulled the rope and oil spit out he line.


Almost have to give it a visual to see if there are any cracks. The oil trick might not be reliable as you can still get some pulse, but it could be leaking. The leak may become more pronounced when the hose is plugged in to the carburetor and pressure can force open a crack that otherwise might stay closed.


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## RKDOC (Jun 20, 2006)

Thanks 30 year I can't see any cracks. Will have to figure a way to pressure/leak test the crankcase.


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## dawgpile (Apr 28, 2008)

Have you checked the exhaust to make sure it's not plugged? It can cause similar symptoms! Good luck!


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## Don L (Jul 14, 2012)

I like to use an aresol can of carb cleaner with the little pastic tube to check for air leaks if the saw will run.When the carb cleaner hits the air leak it will kill it or at least cause the rpm to drop.This works especially well for cylinder gaskets and pulse lines as long as you be sure not to let the carb cleaner get sucked into the carb.Sometimes it's hard to get into the seals without removing the clutch which is a bit of a chore on an 028.
Can't vouch for the safety of this test but I've been doing it for over 10 years in a small engine shop with no problems.
Don:wave:


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