Hydro lock or bad bearings?

[MS290man]

Folks, I’ve got a weird one. MS250, looks like low hours b/c I have 135 psi compression and p/c look like new (as seen through intake and exhaust ports). Saw was run for unknown amount of time without air filter. Couldn’t have been long (I assume) given there is no visible damage to cylinder/piston. The weird thing is that it seems to hydro lock after 4+ pulls. At first I thought it flooded so bad that the case was full but if I pull it through slow it seems to free up after a half dozen cycles. I shut the fuel off completely to rule out flooding (closed both needles) but it still starts to lock up. Also tried a bit of straight 2 stroke oil directly into the cylinder (to rule out piston seizure); no difference. Could this be crank bearings going bad? The owner wants it fixed if it’s simple but he’s junking it if not. Just worried about putting hours into this saw if I have to rip it down to the crank. Thoughts? FYI - when I took it down I realized the starter cord had been repaired (way too short) and the flywheel nut was laying loose in the recoil housing.

 

[Dub11]

Is the fly wheel rubbing on anything?

 

[T.Roller]

Open the throttle up, bring the piston to top dead center or atleast where the piston skirt clears the intake port and tip it back. I'd bet you'll dump fuel out of it.

 

[MS290man]

Dub11 - not that I can see; gap at the coil is good, back side of flywheel clear.
TRoller - I’ll check that, thanks,

If it does have bearings going bad what would be the indications? I don’t feel any grinding or crunching as I spin it over. It just seems really tight.

 

[Wonkydonkey]

So if you took the spark plug out and pulled it over, it can’t hydro lock. But if it gets tighter with the plug out, I guess there’s other problems. If it is flooded it could give you wrong compression reading
It could/would more so hydro lock with just the 2stroke in and plug still in.

I rebuilt a 461 and it hydro locked due to the lube on assembly, what a sum of a bish, my poor digets got a thrashing every time yes x10 it ripped the cord out of my very soar hand/fingers. Till I pulled it hard without the plug.

I’d do what T roller says, and also maybe empty the tank.

It could be a metering leaver valve..stuck open.

 

[Dub11]

Could their be something up with the recoil?

 

[Chainsaw Jim]

Check the clutch for problems.

 

[angelo c]

Dub11 - not that I can see; gap at the coil is good, back side of flywheel clear.
TRoller - I’ll check that, thanks,

If it does have bearings going bad what would be the indications? I don’t feel any grinding or crunching as I spin it over. It just seems really tight.

turn it upside down and pull the recoil a few times after you pull plug and see if some spluge runs down yer arm....

 

[Chainsaw Jim]

turn it upside down and pull the recoil a few times after you pull plug and see if some spluge runs down yer arm....

Wow, I heard leprechauns hated being turned upside down.

 

[MS290man]

UPDATE - so I tore the saw down and found that the plastic ball cage in one of the crank bearings failed and disintegrated. 2 new bearings (upgraded to ones with metal cages) and 2 new seals (while I’m in here) and she’s running like a champ! Now to get a new chain so I can sink it in some wood...

 

[berrnard]

Usually the most logical answer is the right one.

Glad you got it figured out but sorry for all the time in it. [emoji1303]


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