Low compression on my new Stihl MS362

[James Sawyer]

Half my place is timber half pasture and the house. I'm right at base of the Cascade range right up against Timber Company.

 

[stihlguy]

You know, it may just need to be broken in. My 462’s chain stopped many times the first time I ran it. I adjusted my technique and kept cutting. But I ran it for about 1 1/2 hrs that first day. The next day the saw was noticeably stronger. It has been noticeably stronger each time I have run it and I think I have about 4-5 hours on it. I was counting tanks, but lost count. Maybe it’ll come around. I mean they showed you a brand new one is the same so run it like you stole it and it will either fail or not.

+1 mine did the same, lovin' more each time I run it. It takes many tanks to break these saws in.

 

[stihlguy]

We had a family dinner yesterday and I was talking to my nephew about my MS362 and this warranty repair. He's never heard of anyone having a brand new Stihl needing warranty repair. So, I ran a search on this site and came up with nothing. Has anyone had experience with Stihl warranty...just wondering what to expect?

My original MS362 purchased in 2012 kept getting fines into the carb, dealer couldn't correct it, I didn't like it, got a brand new MS362-C.

 

[lone wolf]

120psi cold ...same as the 2nd shop got. The 1st, 2nd shop and I got 110psi on hot compression test.

I still dont mean they have the right setup on the tester either. Any of your friends have a Stihl machine with a small plug test your gauge !

 

[lone wolf]

If you have an adapter on there that will definitely screw with it ! MS 201 Ts stihl blowers Stihl pole pruners all have the small plugs at least the new machines I am speaking of. Dont bet on that compression being that low recheck that gauge like I said. Does the compression feel like **** next to another saw?Poor mans tester have your wife try to start it if she can pull it fast its shot!

 

[James Sawyer]

I start the saw without the compression release it that easy. White wolf...I'm home I'll run out to the barn and see what I have. My power head doesn't have bar on it but I'll see if it falls holding the rope.

 

[lone wolf]

I start the saw without the compression release it that easy. White wolf...I'm home I'll run out to the barn and see what I have. My power head doesn't have bar on it but I'll see if it falls holding the rope.

And compare that to the other saw you have.

 

[X 66 Stang347 X]

Does it run like my 036 with a 20” 33rs chain

 

[lone wolf]

Does it run like my 036 with a 20” 33rs chain

Thats cutting fast whats the wood? Ash?

 

[X 66 Stang347 X]

I believe it was oak,I was cutting it last fall.
I run my chain with .025 raker hight. Even a square filed chain.

 

[James Sawyer]

Do you have any Stihl machines like blowers trimmers pole pruner that has that smaller plug to cross check this gauge?

I went thru all my power tools and the last thing I look at was my wife weed eater which is easy start looks like a 10mm. By time I gotting my tools my uncle Tony showed up he's head to Idaho in morning and needed to borrow some tools. My wife got home and dinner I ran out of time. I'll check it as soon as I can.

 

[James Sawyer]

Oh I hung the power head by the rope it doesn't move. With the compression release it does..slowly steps down the power head is 12.3 lbs

 

[CR888]

I too think your adapter is not allowing the gauge to get a correct reading. With all your engine building experience, I don't understand why you can't remove 4 muffler screws to inspect piston. Have you made sure the spark arrestor screen is not plugged up with carbon (that is 1 screw on muffler outlet).

 

[boltonranger]

So you have another hose that is just like the one you show here with the 460 and 034, except the other hose is 10mm thread instead? Or do you screw your hose into a small piece of metal that is 10mm thread? I have run hundreds of compression tests on cars due to a maniac boss who made us check for every tune-up and buyers check. Not only did the hoses go on the cylinder without additional adapters but the volume of the combustion chamber is bigger than a few cc. The chainsaw combustion is what size? I don't know exactly, by lets just hypothetically say that my 70 cc saw compresses 10:1 so the combustion chamber is 7 cc. then i have my compression tester with schrader in the hose, screw that into a hollow metal adapter that has an air volume of 1 cc, then into the spark plug hole. Now the piston is compressing to 8 cc not 7 cc, that difference would make my saw read 120 when its really 140 psi.

I mean no offense but this is not quite right. The analogy supposes that an adapter or extension on the end of a compression tester will alter its reading. It will not. The reason is because there is already air within the adapter.

Think about it this way...
You blow up a balloon with air- you tie it off and set it on a workbench.

Now put a 5 lb brick on the balloon.
The air pressure inside the balloon goes up by 5 pounds.

Now try the same thing with a bigger balloon, and then a smaller one.

The pressure in all three balloons will always increase by 5 pounds because that’s the weight of the brick.

The volume of the balloons, ie. the amount of air in each one can differ, but that 5 pound brick presses the same weight down on the balloon regardless.

The size of the balloon is volume.
The weight of the brick is pressure.

So a compression tester with a longer or shorter hose may have a different volume of air but the pressure stays the same.

(For simplicity I’m ignoring the force the rubber balloon is squeezing on the air inside it. )

 

[grizz55chev]

I mean no offense but this is not quite right. The analogy supposes that an adapter or extension on the end of a compression tester will alter its reading. It will not. The reason is because there is already air within the adapter.

Think about it this way...
You blow up a balloon with air- you tie it off and set it on a workbench.

Now put a 5 lb brick on the balloon.
The air pressure inside the balloon goes up by 5 pounds.

Now try the same thing with a bigger balloon, and then a smaller one.

The pressure in all three balloons will always increase by 5 pounds because that’s the weight of the brick.

The volume of the balloons, ie. the amount of air in each one can differ, but that 5 pound brick presses the same weight down on the balloon regardless.

The size of the balloon is volume.
The weight of the brick is pressure.

So a compression tester with a longer or shorter hose may have a different volume of air but the pressure stays the same.

(For simplicity I’m ignoring the force the rubber balloon is squeezing on the air inside it. )

There are post after post of the effects that the guage has on the reading, wrong schrader valve in the tip or no valve at all are prime examples of this. Not saying this is the case in this instance, but it’s well documented.

 

[huskihl]

I mean no offense but this is not quite right. The analogy supposes that an adapter or extension on the end of a compression tester will alter its reading. It will not. The reason is because there is already air within the adapter.

Think about it this way...
You blow up a balloon with air- you tie it off and set it on a workbench.

Now put a 5 lb brick on the balloon.
The air pressure inside the balloon goes up by 5 pounds.

Now try the same thing with a bigger balloon, and then a smaller one.

The pressure in all three balloons will always increase by 5 pounds because that’s the weight of the brick.

The volume of the balloons, ie. the amount of air in each one can differ, but that 5 pound brick presses the same weight down on the balloon regardless.

The size of the balloon is volume.
The weight of the brick is pressure.

So a compression tester with a longer or shorter hose may have a different volume of air but the pressure stays the same.

(For simplicity I’m ignoring the force the rubber balloon is squeezing on the air inside it. )

Any adapter without a Schrader valve in the end that screws into the spark plug hole will give low readings.

 

[pioneerguy600]

Due to increased volume above the piston rings, its the same thing as increasing the squish, the compression falls. The adapters causing this are little more than a hollow tube that the 14mm compression end with the Schrader valve screws into, that extra air space causes lower compression .

 

[farmer steve]

Does it run like my 036 with a 20” 33rs chain

can't see the vid. unavailable.

 

[Bwildered]

Oh I hung the power head by the rope it doesn't move. With the compression release it does..slowly steps down the power head is 12.3 lbs

I'd like to see a video of your cutting technique, that could be very telling.

 

[lone wolf]

I too think your adapter is not allowing the gauge to get a correct reading. With all your engine building experience, I don't understand why you can't remove 4 muffler screws to inspect piston. Have you made sure the spark arrestor screen is not plugged up with carbon (that is 1 screw on muffler outlet).

He removed the muffler looked good inside.