Ms880 repair

[MFV]

I’m not sure if it’s the pic, or the angle, or my eyes.
does that bearing cage looked melted a bit with the part of bearing showing in the 7-8 o-clock position? If it is, you should replace crank bearing?
maybe others can chime in if they see same?

It’s like the inner plastic ring is missing a piece I am not sure

 

[MFV]

I’m not sure if it’s the pic, or the angle, or my eyes.
does that bearing cage looked melted a bit with the part of bearing showing in the 7-8 o-clock position? If it is, you should replace crank bearing?
maybe others can chime in if they see same?

 

[MFV]

I’m not sure if it’s the pic, or the angle, or my eyes.
does that bearing cage looked melted a bit with the part of bearing showing in the 7-8 o-clock position? If it is, you should replace crank bearing?
maybe others can chime in if they see same?

It’s not melted it has a chunk taken out of the plastic

 

[michpatriot]

If it was mine I'd be splitting the case and start from square one....especially after all you've been through.

 

[MFV]

If it was mine I'd be splitting the case and start from square one....especially after all you've been through.

Yeah I will take a look at it tomorrow you notice things like clutch side seal basically fell out flywheel side no. bearings seem tight but I need to take a better look at them tomorrow I guess it’s not the race that is damaged it’s the cage nothing looks like it got hot but I will have to sleep on it. Right now I have a stubborn goat out back fixing to kid for her first time it’s kinda all eyes on that for tonight

 

[drf255]

The seals need oil for install, don’t do dry.

That cage looks chipped. Your saw is 3/4 of the way there, I’d split that case and rebearing if I were you.

 

[MFV]

The seals need oil for install, don’t do dry.

That cage looks chipped. Your saw is 3/4 of the way there, I’d split that case and rebearing if I were you.

You are probably right I will price bearings and tools needed.

 

[MFV]

So what do y’all think about a bad decompression valve if I pull on it I can get 10” Hg vacuum I let go and it bleeds down

 

[michpatriot]

The way they're designed compression seals them..I've pushed on them whilst engine is running and you can hear the leak..instantly reseals itself. I think if the carb and muffler were blocked off and you were at TDC and rotated the engine it could unseat but under running conditions you would hear the valve malfunctioning.. But than again how can you vac test with one that pops off the seat..dono maybe there is a vac number that the valve is supposed to actually hold..

 

[MFV]

The way they're designed compression seals them..I've pushed on them whilst engine is running and you can hear the leak..instantly reseals itself. I think if the carb and muffler were blocked off and you were at TDC and rotated the engine it could unseat but under running conditions you would hear the valve malfunctioning.. But than again how can you vac test with one that pops off the seat..dono maybe there is a vac number that the valve is supposed to actually hold..

Good point I will look at it again tomorrow I am already in the house tonight

 

[MFV]

How long would y’all expect one of these saws to hold a vacuum when you are testing it

 

[Yukon Stihl]

I have had them hold vacuum for days.
But i personally like to see zero loss for at lest 10 minutes,same as pressure.
I am sure there are specs from a manual somewhere on the site

 

[MFV]

I have had them hold vacuum for days.
But i personally like to see zero loss for at lest 10 minutes,same as pressure.
I am sure there are specs from a manual somewhere on the site

Ok thanks for the answer I am getting a new decompression valve tomorrow and I will retest

 

[michpatriot]

Interesting, wonder if a leaky valve could lean out a saw to the point of cyinder\ piston damage? I hope some of the resident experts chime in on this one.

 

[MFV]

Interesting, wonder if a leaky valve could lean out a saw to the point of cyinder\ piston damage? I hope some of the resident experts chime in on this one.

I don’t know I can say clutch side seal was loose I am going to keep checking things and messing with things until I figure it out

 

[cookies]

split the case not only to replace the bearings but to also inspect for cracks and gasket failure that can leak when warm

 

[MFV]

split the case not only to replace the bearings but to also inspect for cracks and gasket failure that can leak when warm

All right I going to order bearings and gasket. What do y’all use to press the bearings with. And is there any thing else I need

 

[grizz55chev]

All right I going to order bearings and gasket. What do y’all use to press the bearings with. And is there any thing else I need

Heat, lotsa threads on the subject.

 

[MFV]

Heat, lotsa threads on the subject.

10/4 I will look

 

[cookies]

boil the bearing in water and put the crank in the freezer, should slide on easily by hand or light tapping, work quick before the bearing heats the crank or it will expand it