Husky 394XP New Project

[WolfMann]

Latest update, got the crankcase split today. Used a heat gun and rubber mallet. Took a little while to get up to temp, but once it did the case popped apart easy. Glad I did it, not only for experience, but because once I got the bearings out I realized they were looking kind of rough, and were making noise. Not a silent spin at all. So hopefully by replacing now, I spare myself a headache down the road. Still waiting for some parts in mail, what's been nice is things are showing up a little sooner than expected. With any luck I can get saw back together by end of next week, but we'll see. Here's a few pictures of crank and parts laid out on work table. Sorry the lighting's not the best, got to it later in the day. As always, hope everyone's doing well.

 

[Gord404]

Looking good, a few things I ran across while doing mine was making sure the bearings are fully seated when putting the halves back together or crank doesn't feel right and inserting seals without losing the spring around them, clutch side flush and flywheel side slightly receded the way you took them out, I'm no expert but I Have a friend that is and always asking when not sure.

 

[WolfMann]

Thanks Gord, so how did you end up getting the bearings to seat all the way? Also should they be oriented any particular way? The ones I removed had manufacturer details printed on them facing out. I've been referencing the workshop manual and it just says to heat crankcase and push them in. I've heard of people freezing them first but wasn't sure if it's a necessary step. And I hear ya, I've made friends with local hardware store mechanic, they do alot of husky/stihl work. It's nice to be able to call and ask questions when unsure on something.

 

[Gord404]

Talked to my mechanic friend last night and he said that if they feel too tight when you get your halves together just screw on your flywheel removal tool and give it a couple of wacks and should set them totally in place, - didn't know this when I did my last two I did so I set up some spacers and washers and pulled them in with the FW nut, making sure I had lots of thread as not to strip it and used an old clutch inner on the opposite side and did the same, - the heating of the crankcase halves really helps and think it's necessary in order to get the bearings going in straight, like I said I'm only a beginner like you so it would be good to get some feedback from some experienced chainsaw builders on this subject as well.

 

[WolfMann]

That's a good tip about the flywheel puller, I've read about people tapping on the side of crankcase to relieve tension too.

 

[WolfMann]

Crank bearings successfully installed, used heat gun on sides of crankcase and the new bearings dropped right into place.

 

[WolfMann]

Halfway there.

 

[Ozhoo]

I may have missed it but did you pressure & vacuum test after you scorched it? That lip on a 394/395 crank is tough to get a seal over and you can easily bugger one up to where it won't fail for a couple tanks.

Post up some close-ups of the seals once you get them installed.

 

[WolfMann]

Crankcase is back together, with new bearings and gasket.

 

[WolfMann]

Ozhoo I did not, the seals tested good before saw seized up, but I didn't test after first tank of gas or after the saw seized, was too frustrated to think of it. It could be as you described, going bad after couple tanks. Had a seal lip invert while I was installing, I pushed it back into place, I suppose it could've tested good then, and gone bad shortly after. I'll be sure to post photos, and pressure/vacuum test after first run this time.

 

[decableguy2000]

I would pressure and vacuum test before you run it.

 

[WolfMann]

You're right cableguy, what I meant to say was I'll pressure/vacuum test before and after first run this time.

 

[WolfMann]

Here's saw as it sits now, crankcase bolts are reinstalled, connecting rod wrapped up in paper towel. Probably going to knock off for now, hopefully finish reassembly tomorrow.

 

[rupedoggy]

If you are going to run three tanks of fuel one after the other you are causing HEAT buildup.
1. Do not run 50;1
2. Run rich so it burbles on the top end not SCREAMS.
3. Do not run partial throttle.
4. If it is a hot day, give the saw cool down time.
5. Open the muffler to get some of the heat out.
6. Little microscopic aluminum will not cause your problem.
7. Check the air flow path. The cooling air comes into the starter housing. It is forced up and across the fins. The muffler shield should be in place. The top cover must be in good condition to direct flow. The cold weather flap must be in the closed position. Sending heat into the carb box is not what you want.
8. If you do these things you will not burn up your saw.

 

[WolfMann]

Thank you rupedog.

 

[WolfMann]

Rupedog I'm hoping I can ask for some clarity, what do you mean by open up the muffler? Also what is the cold weather flap? Below is a picture of top cover. Am I missing an element to this?

 

[rupedoggy]

I was just trying to cover all the bases. I don't know for sure if your particular saw has that feature but a lot of saws do. As to open up the muffler. Search the archives for muffler mods. Mike

 

[Ozhoo]

To answer your flap question. 394/395 cold weather shutter gets installed into this groove after you remove the section highlighted. It's p/n 503656701.

 

[WolfMann]

Gotcha, thanks guys.
Here's a few pictures of crank seals, as promised. I've spent the last hour checking for leaks. I can pump it up to 7 psi and there's no bubbles on either crank seal, intake block, or base gasket. I plugged decompression port. However air seems to be leaking past rubber material placed in between exhaust port and muffler, it's slow but reads on the gauge.

 

[WolfMann]

So I kept fiddling and found out there is an air leak right below exhaust port at base gasket. Going to pop off jug and see what it is.