Everything I hate about my new MS290

[dallypost]

But first, to be sure of things, remove the muffler and look at the piston.

If all looks good, go into the carb again, and this time when it is apart, remove the needle/lever/spring and hold the carb up to a light and look through the passage that the needle closes, you should be able to see
light through it.
Blow out that passage with air or carb spray and hold it up to a light again and visually verify that it is clear, then reassmble and try it again.

There is no sign of scratching on the piston or cylinder wall.

I put carb cleaner through every orifice. Everything was visually clear.

The fuel line is brand new, only a few hours on it.

I just cleaned the air cleaner and may have found a hint. When I cracked it open, it was wet with premixed fuel. If memory serves, it has always been dry in the past. Apparently I have fuel entering the filter from the carb. Is this normal?

 

[procarbine2k1]

You need to have someone tune the carb that knows what they're doing. It's not the saws fault that it's not tuned right.

Blunt, but very good advice. The MS290 is an excellent saw for its intended market.

 

[dallypost]

Blunt, but very good advice. The MS290 is an excellent saw for its intended market.

I appreciate this, truly I do. The reality, however is that we ranch in a remote location and we will work this problem out right here. Anyone who can help with this will be greatly appreciated.

 

[Orange Hill]

Maybe your float needle is not seating properly?
How old is your gas and is it more then 10% ethanol? Are you using gas from a tank on the farm or did you buy it at a gas station with decent turnover? I would dump the fuel and start over with fresh gas mixed at 50:1.
It is possible that your plug is fouled or the boot slightly off. What does your plugs insulator look like?
What is the condition of your bar and chain? Does the nose pulley spin freely with your thumb. Are the rails straight and clean? Are the oiler ports plugged. Is the chain clean and sharp? Can you grab the chain on the bar and move it back and forth?
I pulled the caps and cut the tabs off of them and put them back on because they seem to spin too freely without the slight friction of the caps.
If you hold your air filter up to sunlight can you see clean white light through it and are you oiling it? I only ask because I have seen a guy oil his and his saw ran crummy from it.
The best thing I ever did was open up the muffler on my MS390. It is a free upgrade with the only down side is a bit more noise.

 

[stipes]

I'm just wondering??

If there is a vent prob. Odd that it runs great tru a cut then start getting worst...

 

[nate cutter]

I've heard that the wrong fuel filter can act up like this. Did the jet settings change? I pull an old pair (toe) of pantyhose over the air filter.

 

[dallypost]

I always use fresh gas from our local station, though I am not sure of the ethanol percentage. How much is too much? I am also unsure of how quickly they turn their gas over.

I will check the vent, however, I did run a few tanks through before the saw got sick. It seems like a plugged vent would have shown up earlier.

Old nylon huh? Sounds like a good idea.

Thanks

 

[dallypost]

If you hold your air filter up to sunlight can you see clean white light through it and are you oiling it? I only ask because I have seen a guy oil his and his saw ran crummy from it.

When I checked the air filter, it seemed to be coated with fine dust that was a little bit oily. I opened it up and found the inside was coated wet with fuel. I pulled the filter and started the saw. I am getting fuel mist from the carb during acceleration. I assume that this is not how it should run. I suspect that fuel and oil is wicking through the filter causing it to collect and hold fine dust, which eventually plugs it.

 

[andrethegiant70]

When I checked the air filter, it seemed to be coated with fine dust that was a little bit oily. I opened it up and found the inside was coated wet with fuel. I pulled the filter and started the saw. I am getting fuel mist from the carb during acceleration. I assume that this is not how it should run. I suspect that fuel and oil is wicking through the filter causing it to collect and hold fine dust, which eventually plugs it.

This is not unusual, but if it is excessive, it can indicate piston skirt wear. Since your piston is pretty new, it's not very likely that this is the case. BUT.. I suppose there is a possibility that you have a breach in your fuel filter somewhere and have scored the intake side of the piston. It's not as common as a lean sieze but it does happen. I would pop the carb and see what you can see of the piston through the intake port (not an easy deal on this saw). If it seems ok, I would continue to work the fuel supply end of things. If you get no resolution there I'd disassemble and mic the piston.

Honestly, you need to swap in a known good carb to see if it makes a difference. Yes, I know, it's hard to do when you live on a farm in the middle of nowhere... but that is what Ebay is for.

I know I have the sickness (CAD), but I never have just one of my daily drivers. I have two (er.. or four) and keep them both up. One always helps me troubleshoot the other. I know that's not a luxury everyone can afford, though.

 

[Rookie1]

This may be a silly question, but here goes. When I put the carb kit in, I removed those silly limit caps and threw them away. I was surprised to see that the needle valves did not have springs on them. They are held in place with friction only. I wonder it the needles could be moving with vibration, which finally untunes the carb.

When I mess with that style limit caps I cut the tabs off and put them back on. I was under the impression that they needed to be there to keep the needles from backing out. If you feel they are moving remember the turns out and check them.

 

[Jaberwky]

My experience

My saw was doing the exact same thing today and I just about went nuts trying to figure it out. Turns out it was the plug had loosened just a tiny bit and was therefore the culprit of an air leak.

 

[fearofpavement]

What plug? The spark plug?

 

[Wolfcsm]

The filter is original equipment. I really miss the old style foam filters. They are so easy to clean in the woods. Is their a replacement "foam" filter for this saw?

None I have ever found. I keep a second filter in my tool box and replace then and clean the dirty one most days. Filter is fairly cheep on ebay.


Hal

 

[BigMoneyGrip]

What about the spark arrestor screen?

 

[discounthunter]

the saw was running when last used.then you cleaned it. you took the limiter caps off,assuming to take the needles out.did you count the turns the were at? what is your elevation? i think you just have the carb out of wack.

 

[Jaberwky]

?

What plug? The spark plug?

The glow plug. I run a special modded MS290D (diesel).




Seriously though. What other plug is there other than the spark? I'm trying to think and am coming up blank.

 

[cmarti]

The glow plug. I run a special modded MS290D (diesel).




Seriously though. What other plug is there other than the spark? I'm trying to think and am coming up blank.

Some saws have plugs like these:greenchainsaw: