stihl 025 winter/summer shutter

[JONSSTIHL]

Hey guys

with the rapidly approaching cold of winter I was wondering if my 025 has a shutter of some sort that should be moved to help with winter operation. I scored this one for free from a guy I work for but at that price it didn't come with an owners manual.

thanks

 

[Stihl here]

If it does it will be under the air filter cover in between the filter and spark plug. I have the stihl ms250 which is the same saw and it is a black plastic piece that just slides out that lets warm air get to the carb and filter.

 

[Lakeside53]

Take it out and mount it upside down. It's designed that way so you don't loose it.

 

[Stihl here]

Thanks lakeside, I did not know to turn upside down.

 

[JONSSTIHL]

the previous owner must have lost it because the only thing I have is a white/clear plastic shield between the cylinder and the air filter but it looks like I would need to take the saw apart to remove it. it looks like it is the intake mount from searching on ebay for a similar part

I'll have to check out if there are grooves in the top cover that I could slip something in there.

thanks

 

[blis]

huh? not all stihls have the winter flap???

sheesh, another reason not to get stihl in future :hmm3grin2orange:

 

[Lakeside53]

It's a black plastic part that mounts behind the filter. Are you sure it's not there?

 

[JONSSTIHL]

I just went and checked and there is no black plastic piece under the air filter cover aside from the filter box, And I don't see any where that you could slide one into. If someone could post a pic of one installed in an 025 i would really appreciate it and it would help me visualize how this thing is supposed to be installed.

also one more question how big is this thing supposed to be, I'm looking for a plate a little smaller than a credit card but is this thing the size of a dime???

thanks

 

[SteveH]

The one on my 036 is 2" by 11/16", can't miss it.

 

[Lakeside53]

The one on my 036 is 2" by 11/16", can't miss it.

That's quite different...


I don't have an 025 handy, but if you download the owners manual from the Stihl website, it's in there...


Look at part 21:

 

[stihl025]

Here is a pic with the shutter in the up position (shielding the carb from heat) and here is one with the shutter down (winter operation).

 

[WoodTick007]

And what does flipping the over do? Warm the air?

 

[drmiller100]

pulls warm air off the engine to decrease horsepower on really cold days.

 

[Lakeside53]

And what does flipping the over do? Warm the air?

To stop carb icing... nothing to do with "decreasing hp".... and I believe you put in in "Winter" mode around 40 to 50F - It's in the owner manual.

 

[drmiller100]

To stop carb icing... nothing to do with "decreasing hp".... and I believe you put in in "Winter" mode around 40 to 50F - It's in the owner manual.

umm, so you don't think warmer air is thinner then colder air? Thinner air means less horsepower.

 

[blis]

umm, so you don't think warmer air is thinner then colder air? Thinner air means less horsepower.

D'uh!

when outside temp is lower, the air temp near cooling fins is lower too, so in the end, the air is about same temp as it would be in summer setting in summer conditions...

 

[WRW]

I don't know that the temperature of the air off the fins is exactly the same as summer temperatures, but I do feel that icing in the carb will give a more severe drop in horsepower than the warmer air.

 

[JONSSTIHL]

Thanks for the pics stihl025

I'm sure I don't have that part on my saw, must have been lost by the previous owner

the owners manual says you can overheat the saw if you use it without the shutter in the summer. I don't do much cutting during the summer mostly during the fall and spring.

how much is one of those flaps worth

thanks

 

[blis]

Thanks for the pics stihl025

I'm sure I don't have that part on my saw, must have been lost by the previous owner

the owners manual says you can overheat the saw if you use it without the shutter in the summer. I don't do much cutting during the summer mostly during the fall and spring.

how much is one of those flaps worth

thanks

Thats so true, my dad accidently managed to frie a saw that, the temp suddenly went over +0c and there was plenty of snow and that coupled with open winter flap resulted in heat seized husky...

 

[Lakeside53]

umm, so you don't think warmer air is thinner then colder air? Thinner air means less horsepower.

Now you're talking about a side effect - not a reason for using the shutter. Yes, there can be a sight decrease in HP depending on density altitude (assuming the carb was set correctly in the first place), but the reason for the shutter is carb icing.

Be careful with density altitude.. The temperature inside the engine is so much more than the outside that it has much less effect than you may think. It's like the human body - no matter what the temperature of the outside air (within reasonable limits and breathing rates), the density of the air in your lungs is the same because it almost immediately acquires the 98.6 degree temperature of the lungs.


I believe this is "Charles law"... of the three (Charles, Bolye, Henry) guys anyhow