New saw compression

[Marshy]

This post is worthless without pics

Here's a con rod beam as wide my hand.

Here's a piston with cylinder head removed, can't tell size but it's about a 12" bore.

 

[Deleted member 135597]

Well the parts didn't show up today like they were supposed to, or so the dealer says. Sucks because I have some free time to work on it tonight. This is what I don't like about having to go through a dealer. Let me order the stuff online and expedite the shipping if I want.

 

[Deleted member 135597]

Since I'm stuck on parts I was converting all the torques in the shop manual from Nm to inch pounds. ( it's about 1:9 for those of you who are curious) I was reading where they put loctite and where they don't and I saw some bolts such as the cylinder hold down bolts are " waxed bolts" . My question is do they do this for a lubricated torque? Does anyone even follow this stuff and if you do what do you wax it with? I was going to put some bow string wax on the threads.

 

[cstair2000]

Did you replace the piston needle bearing. I am working on a 361 with low compression (no scoring) and putting in new rings and needle bearing while it is apart.


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[Deleted member 135597]

Did you replace the piston needle bearing. I am working on a 361 with low compression (no scoring) and putting in new rings and needle bearing while it is apart.


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No it's like brand new.

 

[Karla]

Woody,
I agree with you, I would inspect, clean it real good, check the bearing fit, and put the same piston bearing back and On Older chainsaws, I replace the piston needle bearings. Just my two cents.

 

[Deleted member 135597]

Dealer just called and my parts are in! I'm like a kid on CHRISTMAS!

 

[blsnelling]

Check your piston clearance with the new one. .002" on the original sounds a little tight to me.

 

[Deleted member 135597]

Check your piston clearance with the new one. .002" on the original sounds a little tight to me.

Yeah wish I knew the clearances

 

[Deleted member 135597]

Ready to run

 

[Karla]

Looks great, and I wish you lots of years of use.

 

[Deleted member 135597]

So right after I finished assembling it my wife came down with the box from the ups guy I was waiting for. It's the new OEM unlimited coil. Murphy's law on the one I guess. Any way I just got done running the saw for the first time. Started after 3 pulls. Ran good. I got the low adjusted and shut her down. Right now the high is still1.5 out. I'm gonna swap out coils now and do a compression test. Tomorrow I will set the high at work.

 

[Deleted member 135597]

And the compression reading was ....................110. Same as it was before I tore it down. Must be the gauge, gonna get another one and retest. If not the gauge, all the original parts, including piston and rings are going back in the saw and it will be headed to the dealer. I got the high set pig rich. It's about 13200 with the tach. I pulled the muffler cover and everything inside looks ok. No scoring anywhere that I could see. I'm going to try and get a bunch of tanks through it within the next few days. I will do the work I have to do with it just in case I bring it to the dealer to sit in the "bin of dead stihls"

 

[Khntr85]

And the compression reading was ....................110. Same as it was before I tore it down. Must be the gauge, gonna get another one and retest. If not the gauge, all the original parts, including piston and rings are going back in the saw and it will be headed to the dealer. I got the high set pig rich. It's about 13200 with the tach. I pulled the muffler cover and everything inside looks ok. No scoring anywhere that I could see. I'm going to try and get a bunch of tanks through it within the next few days. I will do the work I have to do with it just in case I bring it to the dealer to sit in the "bin of dead stihls"

Oh the dreaded bin of dead stihls lmao....I know this is a rudimentary question, but if you hold the saw in your hands, then you grab the pull start cord and gently let go of the handle bar and just hold on to the pull cord what happens.... does the saw drop fast, slow, in stages, not at all????

 

[Marshy]

Oh the dreaded bin of dead stihls lmao....I know this is a rudimentary question, but if you hold the saw in your hands, then you grab the pull start cord and gently let go of the handle bar and just hold on to the pull cord what happens.... does the saw drop fast, slow, in stages, not at all????

Idk why people think that tests holds water. It's only a go/no-go for a blown saw. You could have a trashed piston and ring in a saw blowing 100 psi and it will still lug down slowly in that kind of test.

I think the OP is on the right track, get another gauge and test it. Then run it and recheck after a dozen tanks of gas.

 

[Khntr85]

Yes I do agree with you.... I would say the tester is off.... I was just trying to get an idea since I can't see the saw in person....you can tell just by feeling if that saw has 160 or 110 psi....

 

[Deleted member 135597]

I will see if the saw drops when holding by starter handle just for curiosity purposes. I have the decompression valve out and plugged. I could start it pretty easy.

 

[Deleted member 135597]

First And foremost is A known accurate gauge.

 

[Khntr85]

Yes sir, I am just glad you got her back together and got a good game plan!!!!

Hopefully after you run her for 5-10 tanks she wakes up.... sure as hell should anyway LOL!!

 

[NWCoaster]

Must be a bad gauge.... I think I checked my 461R with a couple tanks through it and it was around 155 psi.