394xp runs good, low cutting power

[stem]

I picked up a late 90's Husqvarna 394xp that starts great and runs/idles well, but is lacking cutting power - somewhat less than my much newer 372xp with the same bar length - 24". It produced 140 psi with a quality OTC compression tester. Just looking into the cylinder from the spark plug hole, it looks to me like it has light scoring. I'm not a good gauge of scoring, but that's what the guy at the local repair shop said when he took a quick look at it. I have tuned the carburetor with a tachometer to the best of my ability. Any other factors that I should be looking at? Crank shaft seal? New cylinder? Or just rings? Carburetor?

Thanks

 

[crzybowhntr]

You're going to get better responses with pics of the p&c, etc.

 

[zogger]

stock answer, clean jug up, new piston and rings, pressure/vac test

 

[CTYank]

Forget the tach bit, except to find the ballpark. You need to adjust the H mixture so you get clean 2-stroking under load @WOT and start to get 4-stroking when you lift. Are you seeing that? Can you get it to 4-stroke? If not, chances are great it's running lean. Not good.

I've seen 2 dealer "experts" really hose things using a tach for carb adjustments. (You "tune" a piano.)

If it's got enough runtime on it, you may want to plan on freshening it up: carb rebuild, fuel & pulse lines, ring(s), maybe piston, maybe cyl, maybe seals. Depends on how sound the bottom end is, and how the investment will pay off for you. Likely best to go through the package once.

 

[Mylesprimo]

My 394xp and 395xp have a lot more grunt power than my 576xp (Not quite the same as the 372 I know). The 576 does have more chain speed though. I am the 2nd owner on the the 394 and the guy who had it before me did a lot of milling with it. I know it needs cleaned up and carb needs adjusted also.

 

[Moparmyway]

Air filter cleaned ?

 

[showrguy]

I remember awhile back that Randy (Mastermind) had a 394 that absolutely drove him nuts, it had no power when opened up...... Just as your describing....
It ended up being the coil was stuck in retarded/starting mode,,,was not advancing............Maybe he'll chime in..

 

[sawfun]

Is the exhaust clear or is the screen clogged up? I have had two stokes start and run well till under a load only to find a resticted exhaust.

 

[MGoBlue]

I'm not a good gauge of scoring

Pull the muffler and post a picture of the piston, you'll get the advice you need on its condition.

 

[William Balaska]

I was thinking ignition as well but 140 psi is on the low side.

 

[Mastermind]

I remember awhile back that Randy (Mastermind) had a 394 that absolutely drove him nuts, it had no power when opened up...... Just as your describing....
It ended up being the coil was stuck in retarded/starting mode,,,was not advancing............Maybe he'll chime in..

I've since seen that on a few other saws.......thankfully I know what it sounds like now.

On this saw though.......I'd like to see a picture of the piston.

Mr. Stem, could you take off the muffler and get us a pic please?

 

[spike60]

Don't overlook a played out clutch on the old girl.

 

[Wood Doctor]

Don't overlook a played out clutch on the old girl.

That "old girl" when running right is the only saw that beat my Stihl 084 cutting 36" dia. logs at the Iowa GTG two years ago. I was running .404 pitch standard full chisel chain and he was using 3/8" pitch skip tooth. He beat me my a nose. To my knowledge, both saws were stock. I know mine was.

I still have the 084 but now it refuses to drop down below 4000 RPM. So, it rests in peace. Dang shame.

 

[stem]

Thanks a bunch guys. I've got a couple busy weeks in front of me, but I'll pull the muffler, dig around a bit more, and get some pics of the cylinder when I get another chance. The air filter is clean. Not sure about the coil, my only experience on other saws is cleaning corroded ground contacts, which definitely put the zip back in.

 

[CapitaineHaddoc]

Just remeber, piston and rings are cheap, if I was you, I'll buy a new meteor piston+caber ring. Most of time, a "lightly" scored piston doesn't remain "slightly scored" for long.

And if you do that, don't forget to delete your base gasket!

 

[decableguy2000]

I've been fooling around with for a while, new cylinders are going to be hard to find, and no after-market, meteor pistons are good to go, coils are not real common used as they’re exclusive to the 394 and 395. I'm not thinking 140 is bad.

 

[MGoBlue]

Just for reference, I brought this jug back to useable condition w/ Randys vids and advice.

 

[nmurph]

I've been fooling around with for a while, new cylinders are going to be hard to find, and no after-market, meteor pistons are good to go, coils are not real common used as they’re exclusive to the 394 and 395. I'm not thinking 140 is bad.

My 394 was blowing 165-ish with a well-worn piston that had a bit of scuffing on one side. I sent it to chainsaw reform school in Tenn last summer. I have no idea what it's blowing now, but it's safe to say it's considerably higher!

The OP mentions possible scoring, and that certainly could explain the low reading and the (perceived) lack of power...pics are needed to decide where to go next.

 

[Sprintcar]

Your saw may be in an overly rich condition also. Follow the instructions on carb adjustments identified on this site and leave the tachs to drag racers. If the lack of power still exist, then pull the muffler and investigate further. A correctly adjusted 394 will chew up and spit out a 372, 575, 044's and some 066's. Don't know about the 084 from Omaha or whats up with all that.

Let us know, now you got us interested.

Chain saw reform school in Tenn, LMFAO.

 

[HuskStihl]

My masterminded 394 went weak in the knees in an "all of a sudden" kinda way. Randy fixed it (for free, cause that's the kinda guy he is), but I can't remember whether it was carb, or coil, or both. I can say without a doubt, that it wasn't low compression.