Husqvarna 365 Special Air Leak to Oil Tank?!

[ChillyB]

So I bought this project saw and knew it needed work. I say that only to explain why I didn't leak test it before pulling the top end. I had already counted on changing the oil seals, and had no expectations except this saw was all there and might be made to run with work.

Tonight I figured to rinse the bottom end with ATF since there was some carbon on the crank counterweights. What do I see but red ATF running out the hole for the oil pump hose. I guess I'm splitting this case after all.

Anyone ever experience a leak between the oil tank and crankcase?

Chilly

 

[Bob Hedgecutter]

Gasket failure and it can happen- but how often do gaskets really fail?
However, if the saw drops a bearing and part thereof does a loop around the crankcase and gets caught at 12 thou RPM between crank lobe and a thin bit of magnesium case- then hell yes, there will be a leak between.

 

[ChillyB]

Split the case just now. The top front hole around the center section was not nearly as tight as the others. The gasket showed no obvious failure. No damage to the cases to explain the leak. My best guess is low clamping force near that looser screw, vibes let the case open enough to leak.

Glad I split it. The bearings are coked up with carbon.

Now to order bearings, piston, and carb rebuilt kit.

 

[ChillyB]

Finally getting close to reassembly, then can clean off my work table.

with cases together without gasket there was SIGNIFICANT gap between case halves at the oil tank to crankcase joint (shining light into oil tank).

Today I taped some 400-grit to a granite surface plate and lapped both halves until I had 95% cleanup. Sure enough, one side required a few 0.001" of lapping to get cleanup at that joint. I will use gasket with light touch of 3-Bond after assuring the crank doesn't bind. I didn't take much off but don't know how much end play I had available before starting. I'll lap a bearing seating edge with a socket if I'm tight.

Now I have ZERO light leakage without a gasket.

 

[Gord404]

ya I do that too with a big piece of in steel and a piece of emery bonded to it if I figure it needs it