Low compression on my new Stihl MS362

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Status
Not open for further replies.
According to the shop its Engineering on the ports on a static compression test, when the saw runs it has higher charge. But no way to prove that! So...I don't know...its tuned right, revs fine, the plug looks good. Its running 13,200 so maybe slightly lean. Heck if I know...but concerning for what I got into it. Makes me wish I bought a Husky. I figured this would be the last saw I'd buy and would be my go too saw.Now my AV034 is again, I won't fall with that MS362. I like the weight, balance and bar length of the MS362... I just don't know what to think. Most professional don't even work on their saws or run compression test, no way they would on a new saw. They run good fuel, clean the filter...the saw doesn't work take it to the shop. Use their back up saws until it's out of the shop. My dad always ran his saws two years then traded it off...kept the newest used saw as a backup. Sometime when money was tight and the new saw got smashed, he'd run that backup until he could afford a new saw. He just keep extra bar in the truck if he got hung-up he could get out with wedges.
 
According to the shop its Engineering on the ports on a static compression test, when the saw runs it has higher charge. But no way to prove that! So...I don't know...its tuned right, revs fine, the plug looks good. Its running 13,200 so maybe slightly lean. Heck if I know...but concerning for what I got into it. Makes me wish I bought a Husky. I figured this would be the last saw I'd buy and would be my go too saw.Now my AV034 is again, I won't fall with that MS362. I like the weight, balance and bar length of the MS362... I just don't know what to think. Most professional don't even work on their saws or run compression test, no way they would on a new saw. They run good fuel, clean the filter...the saw doesn't work take it to the shop. Use their back up saws until it's out of the shop. My dad always ran his saws two years then traded it off...kept the newest used saw as a backup. Sometime when money was tight and the new saw got smashed, he'd run that backup until he could afford a new saw. He just keep extra bar in the truck if he got hung-up he could get out with wedges.
All you need is a person on here wit a similar saw to test his! BS on the 110 being good!
 
Well... you have a few things on your side. Shop mix. 110 from a sister saw at the dealer. Documented. I agree about 110 being low, but- assume the saw fails in the warranty period. There’s enough history to warrant replacement.
IF the saws compression improves, we’ll all have learned something. Meantime Run it. Like it’s normal. See if it gets better.

- “Anyone else out there with a saw like the op that can check their compression and post for comparison?”
 
Quick search says that’s typical. You didn’t by chance check it New, did you?

No I did not, seldom if ever check a new saw as I know they all gain 10 - 15 lbs comp after break in. I remember pulling it over and could tell it had plenty of comp to get it started, felt like 130 - 140 from pulling out the recoil. No new saw I ever ran had less than 130 but compression figures can vary a few lbs from one comp tester to another but not 20 on the low side. These newer Stihls are a total different animal to me though but would really be surprised if they started out at 110 lbs cold comp.
 
No I did not, seldom if ever check a new saw as I know they all gain 10 - 15 lbs comp after break in. I remember pulling it over and could tell it had plenty of comp to get it started, felt like 130 - 140 from pulling out the recoil. No new saw I ever ran had less than 130 but compression figures can vary a few lbs from one comp tester to another but not 20 on the low side. These newer Stihls are a total different animal to me though but would really be surprised if they started out at 110 lbs cold comp.
These strato saws are a different animal, for sure! Throw in the auto tune and you start the learning curve all over. I can see a 20# comp improvement after break in.
 
OK on the way home stopped at another Stihl shop that caters to the area loggers. I ask if they ever check compress on new saws..." yes all the time" it should be min of 135psi if it's not ...something is wrong! It's cover under warranty, leave it and they will take care of it so I did. I told him about my oiler upgraded and showed him the hours on saw plus the Max rpm the other shop ran today. Not a word about not being covered under warranty by my bolt-on's. So ...final word if it's new , under 135psi it's faulty...they said they seen batches of faulty saws before and that's what the other saw shop has with the one they test today off the shelf. The other shop should have taken care my saw without question. Boy that was sure nice to hear. Ticket in hand, made my day.
 
OK on the way home stopped at another Stihl shop that caters to the area loggers. I ask if they ever check compress on new saws..." yes all the time" it should be min of 135psi if it's not ...something is wrong! It's cover under warranty, leave it and they will take care of it so I did. I told him about my oiler upgraded and showed him the hours on saw plus the Max rpm the other shop ran today. Not a word about not being covered under warranty by my bolt-on's. So ...final word if it's new , under 135psi it's faulty...they said they seen batches of faulty saws before and that's what the other saw shop has with the one they test today off the shelf. The other shop should have taken care my saw without question. Boy that was sure nice to hear. Ticket in hand, made my day.
Good dealer.
 
When my saws are brand new I run extra two stroke oil at first so it’s well lubed during break in. At first start up with any new or rebuilt saw I leave the choke on a few seconds longer at every start up. The clear it then cut.
 
OK on the way home stopped at another Stihl shop that caters to the area loggers. I ask if they ever check compress on new saws..." yes all the time" it should be min of 135psi if it's not ...something is wrong! It's cover under warranty, leave it and they will take care of it so I did. I told him about my oiler upgraded and showed him the hours on saw plus the Max rpm the other shop ran today. Not a word about not being covered under warranty by my bolt-on's. So ...final word if it's new , under 135psi it's faulty...they said they seen batches of faulty saws before and that's what the other saw shop has with the one they test today off the shelf. The other shop should have taken care my saw without question. Boy that was sure nice to hear. Ticket in hand, made my day.
dont deal wit the shop that lied!
 
What’s your elevation?

There is a definite difference in compression psi and some calculator for it.

I’ve had saw gain a lot of compression from breaking in. One time, was a China cylinder, I was at around 80 psi after the first run. Let it sit and next day it was 140. Headscratcher till this day.

I’m suprised the first shop didn’t pull the muffler to view the piston. Kinda sounds like they were avoiding something. That’s a 10 minute test and actually more important than a comp reading.
 
What’s your elevation?

There is a definite difference in compression psi and some calculator for it.

I’ve had saw gain a lot of compression from breaking in. One time, was a China cylinder, I was at around 80 psi after the first run. Let it sit and next day it was 140. Headscratcher till this day.

I’m suprised the first shop didn’t pull the muffler to view the piston. Kinda sounds like they were avoiding something. That’s a 10 minute test and actually more important than a comp reading.
500 ft at the house...live in Oregon...foothills of Cascade range.
 
ok...back from the shop. 110psi on their gauge, Stihl doesn't spec compression on their saws the shop said. The shop in no-way was trying to side step my concern. They started my saw several times, ran the compression test 110psi same as I got. I asked them what they thought of that.. they where as surprise as me. I got the impression they never ran compression on new saw? So they pulled a new MS362 off the shelf, never had fuel in it, ran the same compression test 110psi. They took my saw out to their test log (fir ~22") and ran several test cuts...basically full bar length cuts. Nice chips and they where able to put some load on the saw. The chain stopped several time, same as I was having. They thought the saw was fine, possible new engineering on the cylinder and they just test low on a static compression. They would have pulled the muffler earlier and said so but they say the saw runs pretty good... no point. They think I should just run the saw and see how it is once it breaks in...it has .4 hour now. I checked the max they ran on my tach RPM 13,200 during their testing. I don't know...not sure I like these new EPA saw. Makes me appreciate my old school 034av. I think I'll run my camera into the cylinder when I get home just to look around I'm just not feeling great about this new saw.

My 360 consistently 155-160psi... so is my 460, so is my 260.... 110 is low ! If they are trying to say “stihl doesn’t specify their compression” that may be true... however 110psi is NOT normal and a comment like that (without being there to see the entire interaction) is the runaround.... p.s tach idea is awesome! Can you post details on that?
 
Status
Not open for further replies.
Back
Top