I have an FS model something or other and it has been a good trimmer. I'm not totally in love with it w/ a brush blade- for that I prefer the 2 cycle. Trimming is great. For an inspection, just starting and running it up will tell a lot. Look for excessive vibration as the head spins, things like fuel hoses that may be starting to deteriorate etc. Pop the air filter and look that it has been doing its job and hasn't been neglected. My dealer suggested the use of the synthetic oil. You may want to ask what the original owner used. There is a service point on servicing the valve lash to consider. Mine had a fuel cap recall so if you do pick it up, give the dealer a visit and have him check it out

Good points, thanks. I should have mentioned that- this is an older one (I did not see a year mentioned in the online manual, but it makes a reference to West Germany), and is a 2-cycle. But the air filter, vibration, etc, all definitely applies.

Have had same model for 20 years. Never been in shop. Great machine for heavy work, not so great for general "household" chores.

That's great feedback, thank you. Can I ask why it's not great for lighter-duty work? Too heavy, unwieldy, something like that?

This one was probably ~20 years old. It was definitely a 2-stroke, per the manual.

This one's engine was in good shape, 150 psi compression. But there were unfortunately some other issues with the rest of the unit, so I decided to pass. Thank you all for the good info, I appreciate it.

I have an FS85 that I bought used on eBay 8 years ago and love it. I use it on a large lot in Colorado with a bump-feed string head for wild grass encroaching on the driveway (I don't mow) and a brush blade to deal with big, tough weeds. It's perfect for the job (though mowing the weeds at the right time of year would be even more effective.)

Would it make sense to make the seller a low-ball offer and fix the other issues? If the motor's strong and easy to start, that's half the problem solved right there.

The one issue that really concerned me was that the trimmer head was bound/seized up and couldn't be turned by hand. He said it hadn't been used since the spring. I don't know whether it was stored indoors or outdoors. But the head wouldn't turn initially.

After giving it a good twist by hand a few times, we got it to loosen up and turn freely. After that, it would spin when the engine sped up. When you'd start it, the engine would be turning "slowly" (clutch would not engage). But over the next 10 seconds or whatever, it would gradually speed up (with the choke off), and the head would start to turn. I could feel vibration in the shaft when the head was spinning, with no line coming out of the head (so not just an imbalance due to string issues). When you'd kill the engine, with the head spinning, I'd hear a noise from the engine/clutch area as the head slowed down, which sounded like maybe a worn/noisy bearing. Not in the engine, but on the output shaft side, after the clutch (the noise slowed down at the same rate as the trimmer head).

I don't know what was bound up initially, whether down by the trimmer head, or closer to the engine. I don't know whether that vibration, and bearing (?) noise is normal, but they kind of scared me off. Carb tuning, etc, I have no problem with. But I was leery of getting into something where perhaps bearings might seize up on me, in the shaft? Or, again, maybe the vibration & shaft noise are normal.

Some noise and vibration is normal, but it's difficult to say from your description whether this one falls within the normal range or not. I haven't had the shaft off mine, so I don't have first hand knowledge of its construction or possible wear points.

If you're handy and don't mind taking a little bit of a risk, you could research the salvage value of a good motor with a bad shaft on eBay (or just the powerhead alone; might not be exactly the same model, but a range) and make the guy an offer in that area. Get a shop manual (which you should do anyway). Make sure the gear head is properly packed with the right grease (also a must). Then play it by ear. Monitor eBay for whatever you think you might have to replace at a good price. (With the off-season approaching, it's bargain hunting time!) You might end up with a great trimmer at a low price, and even if the shaft craps out you might be able to recover enough from the sale of the motor to make the cost of ownership pretty low.

I'm right in the middle of that same problem.I've had this trimmer for about seven years now and It's been a dependable workhorse with plenty of power but for last two years It's been making clinking sounds,vibrating,head turning while idling etc.Was not aware that trimmers even had a clutch but finally took the four bolts off the front housing and there was the clutch broken in about four or five pieces.I had just recently rebuilt the carb.and was out pulling my arm off trying to get it to run right and found out later that clutch problems will make it harder to start plus it seemed like it locked up two to three times,I was spraying lubricant in cyl. and taking a punch and tapping on the piston top to get it free but it was the pieces of clutch that was locking it.Know this piece is about ten years old but maybe this will keep someone from going through a bunch of unnecessary work or money.If the head is turning while idling It's usually clutch problems.

I've had mine 25 years

General comments: While most problems you will have with the trimmer can be handled by a DIYer, The problem the lead to the lose of my last trimmer was a defective clutch. The clutch house was held in place by screws which is normal, BUT to remove it from the motor, You had to remove a screw deep in the drive shaft. This screw united the drive shaft to the motor shaft. It required a long Allen wrench of small size, that when the torque to remove the screw was applied, twisted the Allen wrench.