MS 180 Issues after Complete rebuild

[Aggie 2012]

Alright, so I got a saw for free about 6 months ago that had been run with straight gas.
Piston was smoked and cylinder was scored.

Not worth fixing on this saw I know but it was my first project saw so I ordered a new piston and cylinder (NWP) from baileys just for the hell of it.

Put it all together along with brand new fuel line, filter, and new carb.

Compression only reads 120 psi and it runs like ####.

See below video with audio and let me know what y'all think. (This is at wide open throttle)

Where do I go from here?




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[alexcagle]

That's really low compression.
Did you check the ring gap in the cylinder?
Maybe they sent you MS170 rings (37mm)
instead of MS180 rings, which are (38mm)?

 

[Aggie 2012]

Hmm I didn't think about that. I guess I need to break it back down and check because I am out of ideas.

Thanks Alex


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[alexcagle]

As you pull the cylinder off, rotate it and you can see the ring gaps in the intake port.

 

[Thommo]

Sounds to be running really lean to me. Can you check for air leaks.

 

[alexcagle]

If it had an air leak, it would idle very high, wouldn't it?
When you test compresssion did you zip strap the throttle wide open, and with choke off ?

 

[HarleyT]

Recheck the intake boot, I have seen a lot of screwups there.

 

[Thommo]

It will idle high if it is a bit lean, but if it is a lot lean it will idle slow and then stall. It sounds like a saw with a leaky impulse hose but the impulse is part of the intake boot on a MS180 so that would be the first place i would check.

 

[Ozhoo]

Puff the muffler and check for scoring... you wouldn't be the first to screw up a rebuild. While the muffler is off do a pressure and vacuum test.

 

[glock37]

What sealer did you use on bottom
Check it for leaks


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[Aggie 2012]

It passed Both pressure and vac testing after the initial rebuild. What should the ring gap be on this saw?
And how would I measure?

Sorry
Newbie questions here but I'm learning.
(Seems that most of my lessons are learned they hard way through experience)



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[blsnelling]

Does your commission gauge have a Schrader valve at the very tip where it screws into the cylinder? Have you used in on another known healthy saw?

Air leak aside, it sounds to me like your not getting fuel.

 

[glock37]

You may have to change carb to a wt 215 they work great


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[Aggie 2012]

This is the compression gauge I've got.

The reading shown is on my old stihl 015l which seems kinda low. But I'm pretty sure it's working because my ms 250 pulls 170 psi.
Might need a new set of rings on this 015 as well?

As mentioned the ms 180 has a brand new carb but I did have some other issues putting this saw back together.


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[Aggie 2012]

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[Aggie 2012]

The NWP cylinder that I bought did not have any of the hole drilled in it so I had to just make my own. Took a little longer but not that big of a deal.

The biggest problem I ran into was trying to get the ignition set correctly against the fly wheel.
I ran out of room or "adjustment play" when trying to get a business card to fit in between the flywheel magnet strip and ignition. (Would not allow it to turn)

So I took a bench grinder and trimmed the magnetic plates on the ignition coil. Everything fit up good afterwards but could that be my downfall?




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[blsnelling]

As mentioned the ms 180 has a brand new carb but I did have some other issues putting this saw back together.

An aftermarket carb?

 

[Aggie 2012]

Well this carb I bought from HL supply for $18.
But I rebuilt the original oem carb with the exact same results


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[blsnelling]

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Does it have a Schrader valve at the very tip where it screws into the cylinder?

 

[Aggie 2012]

No sir. It's right below the gauge here in the photo.
Do you think I could take this thing apart and swap it around?

I guess I need to go home and look at it more closely


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