MS290 trouble

[bama]

My Dentist called me and asked if I would adjust his saw for him. He said it bogs down in the cut, so I cleaned it up, checked the fuel filter(seems to move fuel easily(tank looks spotless) and tried cutting with it.

It doesn't seem to have the power in the cut, but I am out to the stop on the high speed adjustment. The interesting thing is when I tried adjusting the high speed, the saw lost RPM when I went clockwise. I know I need to be out to the stop on high adjustment, so shouldn't the saw try to speed up as I lean it out. The plug is nice and tan and I don't see any scoring. It idles very good and goes up from idle nice and smooth, but can't seem to find the power band.

When I am in the cut and it bogs down, if I pull out and hold it on full throttle for a few seconds, it will climb up in RPM. It sounds lean, but since I am used to old Jonsereds and the "4-stroking", maybe that is what these newer saws are supposed to sound like?

Anyway, I was hoping to tune it up for him and get it back to him for the weekend. I definitely don't want to mess it up or my next cavity might be drilled without modern painkillers!

Point me in a direction, please! Rebuild carb??

 

[stihltech]

limiters

Remove the limiter so you can open the high side a little more.
This saw likes just a little 4 stroking due to the internal jet.

 

[bama]

Thanks, Stihltech. I did a search on removing the limiters. Do I have to worry about the screws moving after I remove them? It sounded like I will be fine and I should try to keep the plastic intact so it is easier to get a screwdrive in to adjust. Am I right?

 

[Fish]

Look closely at the fuel line, especially between the tank and carb, you might
find a bunch of cracks in it. If so, the carb is likely full of sawdust as well.

 

[bama]

Look closely at the fuel line, especially between the tank and carb, you might
find a bunch of cracks in it. If so, the carb is likely full of sawdust as well.

Will do, Fish. Thanks!

 

[mountainlake]

Check the muffler screen too. Steve

 

[bama]

Check the muffler screen too. Steve

Will do.

 

[Lakeside53]

Thanks, Stihltech. I did a search on removing the limiters. Do I have to worry about the screws moving after I remove them? It sounded like I will be fine and I should try to keep the plastic intact so it is easier to get a screwdrive in to adjust. Am I right?

Just slice of the little tab in the side and pop them back on. Then you don;t have to worry at all, no matter who tells you what...

 

[upandcommer]

an often overlooked thig for these ms290's is a plugged airfilter mine was filthy and caused some of the same problems so have him stop buy and buy a new cartridge if his is beyond cleaning or just give it a good cleaning. It might help but heck a 12 dollar fix is alot easier than another costlier option.

 

[bama]

Update

I checked the fuel line. Lots of cracks, but none all the way through, yet(ordered new one). Checked the muffler screen and it is perfectly clean.
Opened up the carb and there was some crap in there so I cleaned it out. The air filter was pretty dirty, but it cleaned up nice.

I took the tab off the limiter, put it back in, opened it up about another 1/8th turn and it runs SWEET!

Thanks for the help, all! Looks like I will get to keep my smile!

 

[Fish]

It has some cracks that are all of the way through, that is where the crap came from. Do not run it much with the old fuel line.
Richening up the mixture to compensate for another problem is dangerous

 

[bama]

It has some cracks that are all of the way through, that is where the crap came from. Do not run it much with the old fuel line.
Richening up the mixture to compensate for another problem is dangerous

Good idea. I will wait until the new hose is on to tune it up. I only ran it for about 2 minutes. At least this is an easy saw to work on! Not too hard to check the carb again.

 

[Lakeside53]

Treat yourself to a new fuel fuel filter while you are at it.

 

[bama]

Thanks, Lakeside.