Another "028 won't run thread"

[Houseman]

Gentlemen, I have lurked here many years and just recently joined to tap into the wealth of knowledge and wisdom here. Maybe, I can share some of my experience too.

A 1985 Stihl 028 was given to me with bad gas in it (replaced), a carboned up plug (replaced), a cracked fuel line (replaced), and a fuel filter with disintegrated foam inner element (replaced).

It now starts with one pull and will idle and rev up to WOT and cut wood fine. After warmed up/cutting, when I release the throttle, it dies. Won't start with many pulls. Let sit 5 minutes, it will start up again, sluggishly, and will WOT fine again. But, it won't idle. Just dies with throttle released. So....the main problem seems to be it won't idle.

I have studied/searched many threads here. Seems like I need to consider:

muffler (doesn't seem to have a screen, unless internal?)
impulse line
carb rebuild
seals (pressure/vacuum test...is this diy possible?)
points/condenser
compression (can I test with Auto style tester?)

Can you help with the diagnosis/repair procedure? What order of attack to pin point the problem? I would like to move beyond the "parts changer" level of diy mechanic.

I've read here that the carb rebuild should include removal of the welch plug for cleaning. Do you agree?

Thank you very much for any help.

 

[deerlakejens]

I'm sure somebody here has an idea or two!

 

[ralawler]

When you say its sluggish does it smoke really bad when you open it up from the idle it does have to wot. If so its way rich. Try screwing the low side in until it starts to idle. maybe adjust the idle screw down to open up the throttle plate. If you don't have a carb problem it should start to idle. your accelaration should pick up. You may have to play a lttle to fine a happy spot.
As you screw the low side in and your idle increases start backing off on the idle screw this will allow the throttle plate to close and decrease your saws idle. I usely set mine just so the chain won,t have any spin. On the high side I ajust just so it will four stroke a little at wot. then put it in wood and adjust for power. Once you've got the Idle set the starting problem should be gone.
I hope this helps , But what do I know I'm an electrical teck. :monkey:

 

[Rookie1]

Ill try a few questions. You should replace the impulse,cheap insurance,to keep it running right. While you have plastic and carb parts off you can get a handheld vacuum pump,like Mightyvac,plug off exhaust port and intake port and pull a vacuum. See if it holds. If it does thats good. If not you have to look for leaks.Mightyvac has pressure port,switch to pressure and pump up spray liquid on seals and look for bubbles.
A compression tester for a auto is fine as long as adapter seals to sparkplug hole and it has a check valve to hold pressure on gauge.
I would probably take carb back apart and clean again really good and consider putting in a carb kit.
I had a problem with my BIL 028 and replaced fuel line/filter and impulse and it was fine then.

 

[Houseman]

Thank you for the information. I tried different carb adjustments without success.

Since it is so cheap, I bought a carb kit and impulse line and will go ahead and install them as the next step. Then, I will consider other diagnostic tests you describe.

One more symptom has shown up. When the saw is held upside down (not running), gas drips, almost pours out of the carburetor. That can't be right.

Thanks again.

 

[Trigger-Time]

Thank you for the information. I tried different carb adjustments without success.

Since it is so cheap, I bought a carb kit and impulse line and will go ahead and install them as the next step. Then, I will consider other diagnostic tests you describe.

One more symptom has shown up. When the saw is held upside down (not running), gas drips, almost pours out of the carburetor. That can't be right.

Thanks again.

I you sure it's coming from carb and not the fuel tank vent?
It should be a hose on left rear under air filter cover, hose should have
to grub screws to keep trash out but still let tank pull in air and I think
it will always leak a little........but it shouldn't run out.

You may have a crank shaft seal leaking, after it warms up.

 

[Fish]

points/etc......

I may be back soon, but since I am not missed, I doubt it.

The officer of my cell block let me have access to the library computer.....

But since no one has missed me, I will not bother to come back........

Just for the group, I am innocent.

 

[Lakeside53]

I missed you.... I was about to start a thread " where's Fish". it's like we're job-sharing, and it's your turn!

 

[Fish]

wow, at least 1 member noticed I have not been around, so my life is not totally a waste..................



Sniff...........................................

 

[Houseman]

wow, at least 1 member noticed I have not been around, so my life is not totally a waste..................

Sniff...........................................

Hey Fish.......you brought my thread back to life..... you are definitely not
"totally a waste". Thanks dude.

The saw in question is running proud again. The carburetor was full of gunk from the disintegrated fuel filter.

About $25 dollars in parts. And........an additional $90 because I just had to have a tachometer to fine tune it. I have relied on the old ear for twenty five years. But because of this site, I couldn't resist the urge to buy another "must have" tool.

 

[Rookie1]

Hey Fish.......you brought my thread back to life..... you are definitely not
"totally a waste". Thanks dude.

The saw in question is running proud again. The carburetor was full of gunk from the disintegrated fuel filter.

About $25 dollars in parts. And........an additional $90 because I just had to have a tachometer to fine tune it. I have relied on the old ear for twenty five years. But because of this site, I couldn't resist the urge to buy another "must have" tool.

Fish will be happy to hear the filter disintegrated. Hes always makin sure guys check them.

 

[lawnmowertech37]

wow, at least 1 member noticed I have not been around, so my life is not totally a waste..................



Sniff...........................................

fish i noticed i even sent you a email wondering if you were ok

 

[Urbicide]

Fish, I thought you were being "detained" at Virginia Beach.opcorn:
(Insert water boarding smiley here.)

 

[kkesler]

wow, at least 1 member noticed I have not been around, so my life is not totally a waste..................



Sniff...........................................

Not just one. Answer your PMs, I've been pestering you for a month or two now and heard nothing but crickets.