Help with seized 394xp

reider · November 17, 2016, 09:49:40 PM

I've had this saw for about a year and half. It has always performed well, until a couple of weeks ago. Cutting on some hickory, it started to slow down. I shut it off but it was too late - seized.

Took it to the Husky dealer. Gave me the bad news: seized and the starting price tag was around $800. They didn't do anything other than confirm that it was seized.

Pulled the cylinder off tonight. Ready to get to work on this thing but I don't know what I'm doing. Watched some youtube videos and rebuilds and read some forum posts.

New piston is a given. Probably need a new cylinder too.

Can I still find a new cylinder for a 394? All my searches are turning up 395 conversion kits. Is converting to a 395 a relatively easy process? And would converting be better than finding a 394 cylinder?

I would really appreciate any help.

Gearbox · November 17, 2016, 10:30:08 PM

there is a reason it seized I would put new seals in it or it may seize again . Chainsawr has kits for the upper end .(see add at left ) . He will also have seals . That 394 is worth rebuilding .

ZeroJunk · November 18, 2016, 08:17:04 AM

It's pretty rare that the cylinder won't clean up unless something broke and gouged a groove in it. And, the world won't come to an end if there are some slight imperfections that won't clean up if they are below the ports. Go to Lowes or Home Depot and get you some Muratic Acid like they use to clean bricks etc. Take a Q-tip and put a little on the aluminum transfer a couple of times. Should bubble up. You can take some 400 grit or so and clean what's left up with your finger. Wait til your wife is gone and put it in the dishwasher. Replace the seals as a matter of course. Meteor pistons work fine for about $40 bucks, or you can use OEM if you want. $800 is crazy.

RIDE-RED 350r · November 18, 2016, 07:31:59 PM

Agree with the above posts 100%!

IF your cylinder is beyond cleaning up, the 395 conversion is your only option unless you find a good used 394 cyl on ebay, forums, or other used saw parts sellers.

She burned down for a reason, replace crank seals, and I would also do the crank bearings unless you know they have been done somewhat recently. But that requires full disassembly of the bottom end and might be more involved than you are looking to get.

You also want to look at your fuel supply components, check fuel line and filter or simply replace them for the few bucks they cost.

The intake spacer on the 394 is known to develop small cracks with time which can cause problems tuning and I suppose burn down in extreme cases. It's a $20 part and probably worth doing for peace of mind. One particular 394 I overhauled would not tune in for the life of me. A forum member pointed me to the intake spacer as a possible culprit and I replaced it, problem solved.

There was another 394 I overhauled that I found had somehow lost one of it's carb/intake mount bolts. This was the cause of the air leak that burned her down...

Definitely worth fixing! But I wouldn't pay $800 to do it because I would do all the work myself. I'm guessing they quoted you the 395 conversion and all OEM parts?? That should still be under $400.... Some kind of labor charge there I think! But they have to keep the lights on too....

reider · November 18, 2016, 11:10:11 PM

Thanks for giving me some direction. I will definitely clean up the cylinder. I would love to not replace that. One thing I noticed when I pulled the cylinder and carb was one of the screws that mounts the carb to the cylinder was loose, it had backed out maybe 2 millimeters. Could that be enough to allow air in and have it run lean?

DelawhereJoe · November 19, 2016, 08:39:59 AM

While looking around to find a ported cylinder kit for my 026 that needs rebuilding, I saw a ported rebuild kit listed for your 394xp at wickedworksaws.

reider · November 19, 2016, 10:17:48 AM

Gearbox, when you say seals, are you talking about on the crank? Sorry for my ignorance but I want to make sure I understand so I can do this right.

Gearbox · November 19, 2016, 06:24:34 PM

Yes crank seals 2 on PTO side 1 on flywheel side . You may want to look for another shop to help with the seals . Just put a new carb boot on and all new fuel lines like some one else said .

reider · November 21, 2016, 08:53:38 AM

Cleaned the jug last night with muratic acid as Zerojunk suggested. The jug isn't perfect. There is some scuffing and most of that is below the port. How can I tell if the scuffing from the seizing is significant enough to need replacing? A new meteor piston is about $40. Is it worth trying and see how it works. If it doesn't, I'm only out the 40 bucks, right?

sharkey · November 22, 2016, 01:45:48 AM

Pull the rings off the piston. Slide the jug over the piston and turn the crank to BDC. Mark through the exhaust port where the crown of the piston stops. Now measure down the skirt to where the rings ride on the cylinder wall. The cyl wall from this point up to the combustion chamber needs to be free of aluminum or it will ruin your new rings. Use a piece of 200 grit sandpaper to rough where the rings will ride in the cylinder after you have used the acid. Use a dressing on your base gasket when you put it back together, I use loctite 515. If you dont have a new gasket, cut one out of a brown paper bag.

ZeroJunk · November 22, 2016, 04:16:22 AM

Quote from: reider on November 21, 2016, 08:53:38 AM
Cleaned the jug last night with muratic acid as Zerojunk suggested. The jug isn't perfect. There is some scuffing and most of that is below the port. How can I tell if the scuffing from the seizing is significant enough to need replacing? A new meteor piston is about $40. Is it worth trying and see how it works. If it doesn't, I'm only out the 40 bucks, right?

Try to figure out if it is damage to the plating or aluminum transfer that has yet to come off. Sometimes it can take a while.

reider · November 22, 2016, 07:04:29 AM

I worked on it about an hour, until the q-tips were coming out clean.

ZeroJunk · November 22, 2016, 06:03:40 PM

Quote from: reider on November 22, 2016, 07:04:29 AM
I worked on it about an hour, until the q-tips were coming out clean.

Have you tried the sand paper ? The plating in those cylinders is very hard. Probably some residual aluminum that is just stubborn, usually is anyway. I have used as coarse as 60 grit. You are not likely to hurt it just using your finger.

reider · November 22, 2016, 07:20:03 PM

Thanks for urging me to use the sand paper. I used it earlier but didn't work it very hard. I spent some time tonight going back at it with the sand paper and it has made a difference. This photo is after working it tonight. You can see some scoring but it is difficult to feel with my finger.

ZeroJunk · November 22, 2016, 10:05:19 PM

Looks plenty good enough to me. Just make sure you find out why it leaned out to start with and you should be good to go.

CrufflerJJ · November 25, 2016, 08:17:30 PM

Quote from: reider on November 18, 2016, 11:10:11 PM
One thing I noticed when I pulled the cylinder and carb was one of the screws that mounts the carb to the cylinder was loose, it had backed out maybe 2 millimeters. Could that be enough to allow air in and have it run lean?

Yes, that could allow extra air into the mix, leaning it out & killing the cylinder.