another Husqvarna 394xp project

[Jeff]

Dooly, I have merged the above post into this existing thread. It serves no advantage and makes no sense to split this off as a new topic.

[dooly]

Sorry about that Jeff. Thanks for making it right.

After a thorough cleaning with kerosene and soapy water, the crankcase halves are heating in the oven. In another 15 minutes they should be ready to smack the bearings out of them.

Looking at the crankshaft now. The small end of the rod can be wiggled back and forth ever so slightly. The big end has a little play along the axis of the pin connecting it to the crankshaft.

Is that to be expected, or do I need a new crankshaft too? I can post sketches to better illustrate the direction of play if necessary.

[dooly]

Heating the crankcase halves to knock the bearings out didn't work worth a hoot. Stunk the house up pretty good, though. A C-clamp and flat bar to press them out did the trick.

I've included a sketch of the play in the rod of my crankshaft. Good or bad?

Thanks in advance for any advice.

[dooly]

Cleaned up my cylinder with diluted muratic acid. Found another dimple higher up in the cylinder.

Is there any way to strip and restore the cylinder lining that is flaking off? How'd they put that on there in the first place?

This jug is in good structural condition. It's just the lining that's the problem. Suggestions?

[dooly]

How do you install the spring within the handle of the chain brake? (See attached photo.)

[sablatnic]

Your connection rod looks fine to me. I would use it. The spring is just pushed in past the holes for the locking pin. If it is like the older saws, it just sits above the locking pin, which sounds silly, but try it. Just make sure to orientate it like the one in the picture.

[dooly]

Got that chain brake handle working correctly. Shoved in the spring like you said and it works like a charm. I don't know how, but is does.

Just finished installing new bearings and seals, and putting the crankcase halves together. The crankshaft is really, really snug and it doesn't rotate easily. It's smooth but very stiff. Is that normal for new bearings?

[Dave Shepard]

No, you probably don't have the bearings seated in the case far enough. I had the same problem when I put mine together. I think I hit each end of the crank with a hard plastic mallet until it spun freely. Careful of the threads on the ends of the crank.

[dooly]

Okay, how to you reinstall those #*%$! rubber bumbers into the crankcase half without breaking them? I got the one in by the flywheel, but I've pretty much chewed up the one that goes near the chain oil tank.

Grrrr. I don't want to have to buy another special tool...

[Bandmill Bandit]

I haven't done a Husky chain saw but the blister in the bottom of the pot/jug indicates a chromed cylinder. Those cant be honed or re-used if there is any scoring checking blistering flaking etc.  at all. Also judging by the suggested price of that pot it would very likely be a chrome lined pot.

Guessing from your description of "your" second failure, the previous owner probably took it apart from what i would suspect was the third or forth failure from pealing chrome in the cylinder and tried to hone out those "flakeouts" in the wall to a point where your last failure ripped enough chrome out to cause the catastrophic failure you now have.

I can't be 100% positive but I can tell you from years of servicing the  Kawasaki snow mobile engines that Arctic Cat used to run, every thing you describe fits a chrome lining failure from an in experienced DIY guy that just doesn't know any better. Stick a honing tool in a chrome cylinder and you have pretty much guaranteed a catastrophic failure.  In most cases once you have a failure where pieces start to break out of the guts it is a "toss it and replace" exercise. That Chrome is so hard and shatters like tempered glass. It cuts its way into every thing and there is no way to get it completely and reliably clean.  

I will do a little checking to find out if husky still uses chromed pots. I know they do on some of their motor bikes. Will update when I get more info.

YES husky chain saws use DuraChrome cylinders! The best kind for performance and cooling but the absolute worst when they fail. It is pretty much a waste of time to rebuild an engine where there is significant damage to the chrome plating on the cylinder wall. It is rare that you will even be able to salvage the crank case.

I went back and looked at all the photos again. Every thing I see indicates Chrome failure. That pot he will give you is worthless. The blister is a result of an attempt to hone it. Check the case with a very strong magnifying glass or get some one to do a mag flux on it for you. That will show any ground in/buried chrome spots. If your lucky it will be salvage able but I have my doubts.

One other note. Chrome pots require chrome rings. Any thing else will last about 15 to 20 minutes max. They expand to much and break as a result.

[dooly]

Got a brand new OEM jug from ebay, which is now installed. Rebuild is almost complete. I have two remaining problems. 1)I don't recall where the 3" to 4" long black ground wire goes, and I can't tell from the parts manual or the shop manual. 2)Had to partially remove the gas tank and somehow managed to mess up the throttle cable at the trigger. Depressing the trigger doesn't open the throttle, but the cable end seems properly secured in the trigger itself.

Any help with either problem would be most appreciated.

[dooly]

Fixed the throttle cable. Secured the ground to a bolt for the plastic cover, one that anchors into the magnesium crankcase.

Pulled the starter rope several times to verify she turned over smoothly, which she did.

Gassed it up and tried to start her. Fired once or twice and stalled. Tried again. Fired once or twice and stalled. Tried a third time, same thing. Upon the fourth try, the starter rope turned, but the piston didn't move up and down.

I think I broke the connecting rod. Dang! This saw is jinxed!

[snowshoveler]

You cut flywheel key...pretty common mistake.
open it up and have a look.
Chris

[dooly]

You were absolutely right, the woodruff key was sheared off. Phew!

Flywheel and starter cover are back. Almost done, but not nearly quite. Read somewhere (perhaps here) that I should make sure the carburetor is set the the "break in" settings. Off now to figure what those are, unless someone here would like to share.

This forum has been an immense help in this rebuild project!

[Dave Shepard]

I don't know what break in settings are. I set mine to the factory 12,500 with a tachometer. It was running pretty rich. I should really retune it now, as it was four stroking at I think 13,000.

[dooly]

Whoo-hoo!

Fired up just fine after backing off each setting screw an 1/8th turn in the rich direction. Will fine tune settings after reinstalling the bar and chain.

Now all I need is a hockey mask.

Thanks everybody!