Hey guys I decided to compression test most of my chainsaws. Wondering if I could get a little feedback on the numbers posted. I ended up testing 9 saws using an Autozone compression tester with the valve thing in the end.
Jonsered 801 - 225 psi
Stihl MS290 - 175 psi
2 McCulloch PM605's - 175 psi
McCulloch Super PM610 - 168 psi
McCulloch PM10-10A - 165 psi
Jonsered 630 - 155 psi
McCulloch 7-10A - 145 psi
McCulloch 10-10A - 135 psi
Honestly I was kind of surprised on the difference between the highest and lowest numbers. The 801 is an old saw, I was surprised it tested so high. It is a beast to pull on and hurts pretty good if it kicks back. Also surprised the MS290 posted a 175, thing has cut a ton of wood and has a ton of hours on it. It is still on the original piston/cylinder/rings.
Also the Mac 7-10 testing at 145, is that low for that model of saw? I feel like it should be up higher with some of the other saws. It's my second biggest saw engine wise but has the second lowest compression. It does have a decomp on it but I made sure it was not engaged while testing. Not sure if that was having a negative effect on the result via leaking air or something.
Wondering what psi = trouble? Is anything lower then 130 time for new rings/piston/cylinder? Any of the above numbers look way off for that model of saw?
Anyhow any feedback given is much appreciated. Apologies if some of this info is posted up elsewhere in the forums.
Thanks,
Jake
Jonsered 801 - 225 psi
Stihl MS290 - 175 psi
2 McCulloch PM605's - 175 psi
McCulloch Super PM610 - 168 psi
McCulloch PM10-10A - 165 psi
Jonsered 630 - 155 psi
McCulloch 7-10A - 145 psi
McCulloch 10-10A - 135 psi
Honestly I was kind of surprised on the difference between the highest and lowest numbers. The 801 is an old saw, I was surprised it tested so high. It is a beast to pull on and hurts pretty good if it kicks back. Also surprised the MS290 posted a 175, thing has cut a ton of wood and has a ton of hours on it. It is still on the original piston/cylinder/rings.
Also the Mac 7-10 testing at 145, is that low for that model of saw? I feel like it should be up higher with some of the other saws. It's my second biggest saw engine wise but has the second lowest compression. It does have a decomp on it but I made sure it was not engaged while testing. Not sure if that was having a negative effect on the result via leaking air or something.
Wondering what psi = trouble? Is anything lower then 130 time for new rings/piston/cylinder? Any of the above numbers look way off for that model of saw?
Anyhow any feedback given is much appreciated. Apologies if some of this info is posted up elsewhere in the forums.
Thanks,
Jake