2171 Rebuild/Maintenance Question

[Alphadelta]

Hey all new here.

So I got a non running Jonsered 2171 at an auction, and have been slowly making her my lifetime saw. Got it running, new filter, new, sprocket, chain, bar, etc...

It runs really well now, no complaints. But I was watching videos and one guy did a compression test to see if there were any issues. I did the same; curious since this saw was run hard and put away wet. I am getting 100 psi on the dot, thats cold saw with the throttle wide open. I am using an automotive compression tester since a chainsaw one from baileys is expensive. But my reading on the forums is telling me thats low, that it should be around the 150 mark.

The question I have now is, should I be worried? And who do I go to for a rebuild kit? Part of me wants to overhaul the whole saw but rule # 1 "don't fix what aint broke" is probably going to be my approach.

I would love any insight anyone has. I've been looking at the Husky 372 XP rebuilds, and people seem to be buying these big bore kits but not sure I need that. I need reliability vs performance.

Much appreciated in advance!

 

[deaves61]

Hey all new here.

So I got a non running Jonsered 2171 at an auction, and have been slowly making her my lifetime saw. Got it running, new filter, new, sprocket, chain, bar, etc...

It runs really well now, no complaints. But I was watching videos and one guy did a compression test to see if there were any issues. I did the same; curious since this saw was run hard and put away wet. I am getting 100 psi on the dot, thats cold saw with the throttle wide open. I am using an automotive compression tester since a chainsaw one from baileys is expensive. But my reading on the forums is telling me thats low, that it should be around the 150 mark.

The question I have now is, should I be worried? And who do I go to for a rebuild kit? Part of me wants to overhaul the whole saw but rule # 1 "don't fix what aint broke" is probably going to be my approach.

I would love any insight anyone has. I've been looking at the Husky 372 XP rebuilds, and people seem to be buying these big bore kits but not sure I need that. I need reliability vs performance.

Much appreciated in advance!

Normally they run around 145 to 150 compression wise, could be the gauge, but it might be worth the time to pull the muffler and take a look at the piston. Oem cyls are hard to beat, my experience not much difference between oem and big bores.

 

[Alphadelta]

Normally they run around 145 to 150 compression wise, could be the gauge, but it might be worth the time to pull the muffler and take a look at the piston. Oem cyls are hard to beat, my experience not much difference between oem and big bores.

So I did pull the head off to clean the cooling fins they had caked on tar (saw was a used fire dpt piece) and the cylinder and piston looked good with what appeared to be some very minor scoring on a small portion of the piston <25% of the surface. Everything else looked really good. I am beginning to think the compression tester is just junk.
Could that minor of scoring cause an issue?

 

[cuinrearview]

If it's running fine just keep cutting with it. That little mark probably won't hurt a thing.

 

[Alphadelta]

Sounds good. Local chainsaw guy is going to look it over when I go pick up my felling dogs. Since its running and, frankly running well, unless the guy finds something insane, I will leave it until this winter as a project.

One last question though. Is the Jonsered 2171 and Husky 372XP identical as far the power plant is concerned?

 

[cuinrearview]

One last question though. Is the Jonsered 2171 and Husky 372XP identical as far everything except the handles and covers is concerned?

Yes

 

[Edweiser]

If it starts, idles right and runs strong don't even worry about or bother with compression numbers. If it starts feeling like there's no spark plug in it when you pull it over and is lacking power that's when it's time for a new top end kit. If you wanted to be fussy you could deglaze it and new rings, but I'd say run it. I wouldn't pay anyone to look at it, sounds like you already did a good job with it

 

[Yotaismygame]

The first thing that should have been covered with that low compression reading is the tester. Does it have the valve down at the end or up in the gauge? If its up in the gauge it wont read correctly for small engines.

Like others said, if it runs good it doesnt matter.

 

[Deleted member 117362]

You already had cylinder off, why not just re-ring it and check compression after a short run in. If compression has increased, with same gauge., you have a baseline for your saw. Then you can check compression every once in awhile for a quick wear check. I would put a small amount of 2 stroke oil in cylinder and see if you get a good pick up in compression, if you do, new rings for me. At this 1000 ft altitude and my gauge if a 372 of mime only has 100psi, not going to run it and will get re-ringed and v/p check. Agree with deaves61 a 145-150 is a normal compression reading. Caber 50mm x 1.2mm (2 ring piston) 50mm x 1.5 (single ring) are around $15 for 2 rings, oem $35 for 2 rings.