MS260 hot running problem

[Graham]

When I start this saw from stone cold it'll run perfectly for about 20 mins then start missing and spluttering. It can be kept running of a sort by flicking choke on and off. If the saw's left to cool a little then it'll be fine again for a few mins.

 

It feels like fuel starvation or a tank vacuum. All fuel lines etc are good, new diaphragms and carb blown through with airline. Fuel issues seem to have ruled out.

 

Could it be developing an air leak when hot? Any suggestions welcome.

 

Thanks.

[slack ma girdle]

Check the rubber tube between the carb and the piston, it does have a propper name but i can not remember what it is called. It is also worth checking the tank breather valve. Other than that, scratch you head and sack (you decide which order) and hope somebody come up with a better answer.

[craig]

Graham, have you been usin the "shutter" for winter operation and not change it back for summer use??

[Dean Lofthouse]

Graham

 

I can tell you exactly what it is

 

You will have to be able to take off the carb to solve the problem.

 

If you look at the carb, on side will have a chrome plate secured with four screws one on each corner, the other side will have a cast plate secured with one screw in the middle.

 

Undo the plate with the one screw in the middle and remove the plate.

 

This is where your fuel enters the carb and you'll find a small round hole about 8mm diametre with a mesh/gauze filter in it.

 

You'll find that this mesh filter is blocked with brown gunge. Give it a blow out to clear the gunge and reassamble

[armchairarborist]

wow Dean its like as if you can see right into it from there.. any idea why my passenger door wont open at all?

[Dean Lofthouse]

wow Dean its like as if you can see right into it from there.. any idea why my passenger door wont open at all?

 

It's not phsycic, you've got to press the button from the outside or pull the lever from the inside.

 

Failing that the linkage to the door catch has come adrift

[Dean Lofthouse]

Forgot to say, be real careful if you use an airline to blow the gunge away from the gauze filter as you may blow the gauze out and lose it

[Graham]

Graham

 

I can tell you exactly what it is

 

You will have to be able to take off the carb to solve the problem.

 

If you look at the carb, on side will have a chrome plate secured with four screws one on each corner, the other side will have a cast plate secured with one screw in the middle.

 

Undo the plate with the one screw in the middle and remove the plate.

 

This is where your fuel enters the carb and you'll find a small round hole about 8mm diametre with a mesh/gauze filter in it.

 

You'll find that this mesh filter is blocked with brown gunge. Give it a blow out to clear the gunge and reassamble

 

Cleaned out that gauze filter. Think I've cleaned out that carb 5 times now! I'm going to check it again now though.

 

Thanks for replies.

[Dean Lofthouse]

You have to be awkward dont you Graham

 

Vacuum could be ruled out by undoing cap and trying to start again.

 

Could also be an electrical breakdown problem in plug or coil.

 

I have two saws and swap parts over to eliminate one thing at once coil wise etc then you can definately pin it down to fuel or airleak

[Graham]

I was born awkward:001_smile:

 

This saw has driven me nuts. Fixed saws for years but there's always one.

 

Doesn't seem a problem on the electric side as swapped electricals from another saw.

 

I'll try swapping carb and see what happens.