Stihl 028 AV Super - Powerless when warm.. Help?

[SEAM]

Another possibly remote idea might be loose cylinder mounting bolts...

 

[ShockValue]

Thanks for the suggestions so far. I'll be working through them as I have time.

I know the muffler is OK. I took it off last week, pulled out the spark screen and took some oven cleaner and a wire brush to the rest of it. It's shiny!


Last night I was going to run it for a few minutes. Interestingly it was sitting in the sun all day on the back porch (and it was actually pretty warm here yesterday) and it ran like crap from the very beginning... Pre-warmed up, or just totally hozed now I wonder....

 

[ShockValue]

Also since I was monkying around with it, I revved it up for a minute and hit the kill switch. Spark plug (relatively new) had a tan color to it. I've read that's "normal".

 

[Rockjock]

Thanks for the suggestions so far. I'll be working through them as I have time.

I know the muffler is OK. I took it off last week, pulled out the spark screen and took some oven cleaner and a wire brush to the rest of it. It's shiny!


Last night I was going to run it for a few minutes. Interestingly it was sitting in the sun all day on the back porch (and it was actually pretty warm here yesterday) and it ran like crap from the very beginning... Pre-warmed up, or just totally hozed now I wonder....

OK it is not the physical appearance of the muffler remove the muffler and look at the piston and see if it is scored or scratched.

pic from google search.

 

[ShockValue]

I little discoloration but no large scoring marks I can see. I moved it up and down a bit and it all looks like this -

What is this bottom part do?

 

[SEAM]

The fuel line looks like it has ruptured just above the tank grommet...

 

[erikvr]

How is the compression, does the rope pull out easliy?

 

[Duane(Pa)]

The white thing with the screw in it is a cover for part of the anti-vibration system.

 

[erikvr]

I was trying to look at the fuel filter but the hose is VERY short on mine for some reason. The line doesn't have enough slack in it to get the filter out of the tank.. If I pull the filter off, I'm going to have a heck of a job getting it back on.

If it is that short the filter could probably not reach the fuel when the tank gets empty. Normally fuel lines are on the short side, you have to stretch it a bit and use plyers to get the line out.

 

[sld961]

If it is that short the filter could probably not reach the fuel when the tank gets empty. Normally fuel lines are on the short side, you have to stretch it a bit and use plyers to get the line out.

A hemostat is great for pulling fuel line out.

 

[bag-o-donuts]

Probably a good idea to replace the fuel and impulse lines just for g.p.

 

[fearofpavement]

Here's my guess: Pull the carb, clean the filter screen inside the carb, put it back together and try it. 15 minute job.

 

[ShockValue]

Going to start with the simple.. Clean carb. Then check/replace lines. Will report if it helps or not.

 

[steve siri]

Same issue (top of thread) as I had. Replaced the impulse hose and tank vent. Runs like a charm now