Stihl ms880 running lumpy

[combined tree services]

hi guys , we required our 880 on a job today but when we fired the saw up it would not idle , as soon as you blip the throttle and take it off of half choke it imediately dies , if you keep the revs up you can use it but to my mind this aint right but to rule out stale fuel we ran 5 tanks full through the saw but still its not happy ticking over , if you can get it to tick over the tickover speed will not be constant and when you do then pick the saw up and so much as touch the throttle id stalls .

 

Having looked at the carb mixture settings i can see that the h/l jets have the anti tamper covers so in theory it can not be out of tune or messed with by one of the staff .

 

So does anyone have any advice as to what may cause this ?

 

Cheers in advance

[spudulike]

hi guys , we required our 880 on a job today but when we fired the saw up it would not idle , as soon as you blip the throttle and take it off of half choke it imediately dies , if you keep the revs up you can use it but to my mind this aint right but to rule out stale fuel we ran 5 tanks full through the saw but still its not happy ticking over , if you can get it to tick over the tickover speed will not be constant and when you do then pick the saw up and so much as touch the throttle id stalls .

 

Having looked at the carb mixture settings i can see that the h/l jets have the anti tamper covers so in theory it can not be out of tune or messed with by one of the staff .

 

So does anyone have any advice as to what may cause this ?

 

Cheers in advance

 

My advice on a saw of this value is to get it to a service technician and get it pressure checked, compression checked and then get the carb reset if all OK, a lumpy idle or change of idle properties is a possible sign of an air leak but in general raises the idle speed rather then dropping it.

 

The saw may just need a tweak but something else may be wrong with it but the bottom line is to make sure the top end revs are within spec and is in no risk of seizing - a new P&C is £400 without fitting:thumbdown:

 

One quick check is to check the plug colour by stopping the saw halfway through a big cut - should NOT be bleached white or very clean - a tan colour or tan grey colour is OK but isn't the best check - using a tach is!

 

Simple ones to check are that the air-filter isn't filthy or the fuel filter isn't partially clogged up and the plug condition and colour.

[combined tree services]

had a look at the plug and its a nice biscuit collour , the air filters are cleaned daily and fule tank and filter is all clean . to be honest one of the problems in being down here in cornwall is that there aint any decent firms near me that know there stuff on bigger saws .

[spudulike]

had a look at the plug and its a nice biscuit collour , the air filters are cleaned daily and fule tank and filter is all clean . to be honest one of the problems in being down here in cornwall is that there aint any decent firms near me that know there stuff on bigger saws .

 

Mmmm - finding that this is pretty well spread, seems most repair centres use their best techs on more expensive kit and don't appreciate that chainsaws are the GP cars of the garden world:thumbdown: or just sell new kit!

 

IMO, a change in the idle can be signs of something not being right - just fixed an MS880 for being lean - it seized and the H screw was around 1/2 out when it should be around 1 turn - the plug whas white:001_rolleyes:

 

Your plug colour sounds fine - it may just need a tweak to the L screw and idle but best left to the tech with a good ear or better still, the tach reading - expensive saw to cock it up on!

[combined tree services]

Hmmm where abouts are you ? i could sent you the unit but in guessing you would need a bar and chain lol .

[spudulike]

Hmmm where abouts are you ? i could sent you the unit but in guessing you would need a bar and chain lol .

 

I am in North Hertfordshire and seem to have most of Arbtalks broken saws in my workshop:001_rolleyes:

 

To tach a saw correctly, the bar and chain used on the saw should be fitted to supply the correct drag and friction on the saw - if a varying selection of bar and chains are used, the max revs should be set with the shortest bar used as this will make the saw rev higher.

 

Shame you aren't a little closer - a 36" bar and Stihls largest in the post would be interesting:lol: Picked up the one in "Whats on my bench" thread when I was on holiday - much to the wifes dismay:thumbup:

[combined tree services]

lol we run the saw on both 36" and 48" however i have another 880 in a box of bits lol maybe i will bring the lot up to you next time im up . i would rather have one saw that runs one bar rather than changing them every now and then

[tommer9]

TAke it to see simon at portreath garden machinery.

[combined tree services]

TAke it to see simon at portreath garden machinery.

 

is he any good ? and whats the waiting time like ?

[JAMIE1]

I have an 880 sat on the shelf waiting to be looked at, i got it posted to me using DHL at a cost of £11 thats with a 30 inch bar and chain. Problem with that one is that the fuel leaks into the cylinder when the saw is not being used then it wont start because its flooded. I suspect all it needs is a carb kit, im hoping so anyway.