Stihl ms390 wont stay running?

[Pullinchips]

Alright my saw started with a fluttering idle and would bog down and cut out.  Then would run wide open.  Left it and tried again and it would run made a few cuts in solid green 17'' oak no problem.  As a side note the saw has recently started leaking all the fuel out the tank slowly you cant see it drip.  Then i went to cut the logs up and would not run again wot then flutter the let it idle then would die once you grabed the trottle, sometimes an easy restart sometimes would not and needed a choke to start.  Went to use it the other day to trim limbs, no prob. , wide open, over head off camber angles for several mins then finished trimming.  This problem will occur at all fuel levels from low to full.  I put the carb kit in and blew out all the passages with spray yea i know thats not the best way.  Pulled the fuel filter and put the line back in without one and still would not run just idle the cut off or wot then flutter and let off and then cut out?  Any ideas, i can give more info if yall need anymore info.  Saw is a MS390 i bought it new in 2004 and have never had to do anything to the saw and cut several truckloads of firewood a year.

[Pullinchips]

oh, i pulled the plug and it looks like a used plug but no buildup or anything that would affect performance.

-Nate

[NWwoodsman]

Maybe a new fuel line, could be a hole in it if it's leaking fuel. Had my 390 go out on my a few weeks ago, scored piston and sleeve. Don't think thats your problem as it just went and didn't cut again. I've had alot of fuel lines go out on me over the years and it sounds like that may be your problem.

[tlandrum]

if you use gas with ethanol first thing id do is get a $12 carb kit and istall it.ckeck your impulse line for cracks.

[Pullinchips]

i agree i dont think its anything related to piton or engine damage.  It will run fine at some point so its not piston issues! i was also thinking sucking air myself.  It s definitly fuel or spark related and im thinking fuel. I was thinking sucking air which is why i pulled the carb thinking a gasket was bad. I will try a new fuel line as it is cheap, probly that stupid ethonol.

[Pullinchips]

put the carb kit in i ordered it at first sign of problems.  Ok whitch one is the impulse line?

[STIHLFULLSKIP]

290\310\390 series saws are great saws.but they do seem to be rough on fuel lines.does anyone know why???

[windthrown]

I dunno why they go out early, but the fuel line went out on my 290 after about 4 years. They are prone to cracking for some reason. The saw would not start at all when the fuel line went out though. I doubt that its ethanol. Chances are its the fuel line, or the impulse line. Sounds more like the impulse line to me. The impulse line drives the fuel pump at the bottom of the carb, and connects from an elbow fitting at the bottom of the carb to a nipple at the base of the cylinder. It is a small black corrugated rubber hose, about the width of a fuel or oil feed line. In some saws they are a real bitch to replace. A leak in the impulse line and the saw will run real funny and erradic.

[Pullinchips]

Pulled the fuel line out of the tank and off the carb yesterday there are 2 cracks between the last 2 corregated sections into the tank.  I hope this is the problem as that impulse line looks like a bugger to change.  I m sure im sucking air to some degree through this which would explain the flutter to not running atall as well as the leak.  New line is in the mail cross your fingers for me.

[Pullinchips]

bought a replacement off of ebay, which was aftermarket.  Save your money and time the grommet was visibly smaller and leaked fuel.  The guy sent me another free of charge and it too was the same, at least he is returning my $ minus the original shipping.  Called stihl and was actually the same price or a little cheaper $10.50.  I just wanted it shipped to the house as i rarely go the direction of town 1/2 hour away.  Problem solved running saw and no leaking fuel.  Also have a new starter rope and rebuilt carb now, carb was not needed i just had the kit and though it may have been it at first.

[ErikC]

 Yesterday I bought a new fuel line and pickup for my 290, for this same problem. Cracked fuel line right above the tank, no doubt ethanol is the main factor. Anyway I put it on this morning and all is well, these repairs are a fact of life these days, as anyone with a few saws well knows. $13.00 for the line at a stihl shop.