Stihl ms 440 not running well when cold

[outdoorfan]

I will do that. I just don't think that is a realistic solution to the problems that it's been having. Wouldn't it be great if that's all it is, though!

 

[outdoorfan]

I will do that, after checking for cylinder damage.

 

[outdoorfan]

Piston and cylinder look okay to me, but please correct me if I'm wrong. Saw started up fine and ran great from warm shed (running it outside in the cold air, of course). Now I have it sitting on the ground outside cooling off for the next test.

Edit: I got the piston and cylinder pictures labeled backwards. Should be obvious to you guys who know what to look for. Sorry about that.

 

[blsnelling]

Looks good. Inspect your intake boot, impulse line, fuel line, and filter. Clean the carb and install new diaphragms.

 

[outdoorfan]

Sounds good. All those things are on order. Spark plug too.

 

[blsnelling]

Check the tank vent as well. You can remove or loosen the fuel cap to test that when it's acting up.

 

[pioneerguy600]

That piston and muffler look very dry to me, a little richer fuel setting would help a good bit.

 

[outdoorfan]

Ok, thanks for you comment. I will find out soon enough when I try to fire it back up after sitting out in the cold. I will richen up the high speed jet.

 

[pioneerguy600]

That is just one of many things that could be wrong with your particular saw though. The 044 and MS 440 are still my all time favorite saws in the Stihl lineup with the oldest one, my first 044 reaching the end of its life cycle with more than 3,000 hours on it in the bucking up hardwood firewood business. Been totally rebuilt back 5 -6 years ago around 2,000 hrs it is just basically wearing out at this stage but I have 6 more in running form and a half dozen waiting their turn for rebuilds.

 

[mountainlake]

Give both the high and low 1/4 turn out, you always turn them back if it doesn't help. Steve

 

[HarleyT]

You need to stop until you can go through the carb properly, and rebuild it properly...

 

[mountainlake]

You need to stop until you can go through the carb properly, and rebuild it properly...

I'd sure try adjusting it a little richer before rebuilding the carb. If adjustments don't help them chase other problems. Keep it simple. Steve

 

[HarleyT]

You shouldn't try to "adjust" a running problem.

It never ends well.

 

[HarleyT]

Fix the problem.

 

[outdoorfan]

Adjusting the carb didn't make any difference. I should have some parts in a few days.

 

[mountainlake]

I wound never start diagnosing a saw running problem without adjusting the carb to see what happens. If turn the screws out 1/4 turn or so (not 2 turns as that would be covering a air leak or something else) and that made it run good fine , no problem. In this case opening the screws made no difference pointing at a clogged carb, clogged filter or screen , bad fuel or impulse line. most of which have been mentioned. Steve

 

[mountainlake]

You shouldn't try to "adjust" a running problem.

It never ends well.

Were not talking about opening the carb up 2 turns, if 1/4 turn made it run good blame it on cold weather. If you don't think saws need to be adjusted between hot and cold weather you really shouldn't advise any one. Steve

 

[HarleyT]

if 1/4 turn made it run good blame it on cold weather. Steve

So next summer, we should all go ahead and turn our mixture screws in 1/4 turn on all of our equipment?
What about a warm spell next week? Or when it warms up this afternoon?
1/4 turn is quite a lot of adjustment, don't you think.
If you have to adjust your saw 3 times a day, you really shouldn't be giving any advice here......

 

[mountainlake]

They should be adjusted so they run good for the temperature , it could be just a little or more and no you don't have to adjust 3 time a day but they will need to be adjusted when going from 85 f and humid to 20 f and dry air, trying to say they don't need to be adjusted for temperature changes is bad advice. Keep in mind adjustment aren't written in stone, I mentioned 1/4 turn as that should have made his saw run way rich if the carb was working right and then he could turn it back in until it ran good. You leave yours adjusted the same all year and I'll adjust mine when they need it. Steve

 

[HarleyT]

Ok, for the sake of this discussion. Say his saw is 7 or so years old.
Now, last fall, after 7 years, his saw starts running poorly. After 7 summers, and 7 winters....
You say, back both screws off 1/4 turn.
If the saw runs better, then your saw is fine....
Fixed.

It was just the cold weather......