FS110 low power

[mtnwkr]

I bought a really clean fs110 with the bike handles at the beginning of the summer. When clearing grass it seems to drop the rpm's more than I would expect it too. Even just 6" of grass slows it down. Is this normal for these 4mix engines? Compression is good, valves adjusted, muffler screen was clean, good fuel mix, starts and runs good till a little grass gets wrapped up in it then it slows till its clear. P&C look good from the muffler side.
I've cleaned the plug and the air filter but haven't changed them. Anything else to check?

 

[Mike C.]

Never heard about that. Is it possible that the sound of a 4mix throws you off, to where you think it isn’t very powerful. I used to think that about my 91 until I got used to the sound. The 4mix don’t rev very high, but they do have a lot of torque

A neighbor of mine hires me yearly to do a massive amount of high-grass cutting on his property.My old Shindaiwa was no longer up to the task,so he bought a new FS 110 with the bike handles.I had a hell of a time getting used to the 4-mix engine not winding up instantly like a 2-stroke.I used the machine for the entire week, finished the job and,honestly was not very impressed with how it ran.It would idle like a car all day,would run somewhat decent at full throttle,but was very sluggish at mid throttle.I had the carb tool that fit it,so I tried adjusting the carb and it really made no difference.I guessed that that was how it was supposed to run-which I thought sucked.

Before I gave it back,I used it on my own property and it was really running like a turd,in my opinion.The owner took it back to the dealer at my suggestion and they wound up putting a brand new carb on a week old machine.Dealer said they had a lot of problems with those carbs.Might be worthwhile to just buy a new carb(did you adjust it?)

Edit:Forgot to add-With the new carb it runs well and has a *hit-ton of power.An FS110 should act like a foot of grass isn't even there.

 

[backhoelover]

Check valve adjustment and cam

 

[backhoelover]

Those trimmer will carbon up if keep throttle low

 

[Mike C.]

Check valve adjustment and cam

I've heard rumors that those engines have plastic cam lobes,is this true?

 

[Mike C.]

I didn’t adjust my carb. Mine ran well without adjustment or putting a new one on

In my long-winded way,I was replying to both you and the OP.I was merely agreeing with your statement that the 4-mix engines can "sound" like they're not running well,or revving as they should,if you're used to a 2-stroke.

In my case,the engine really did have a problem,that being the carb.Ididn't want to believe it based on my lack of experience with those engines,but something just seemed off.

 

[backhoelover]

Yes they are. Ones I’ve had to change were on units that the customer removed the guard. Or a loose backing plate that holds the compression release.

 

[dmb2613]

I don't think you can see the piston with the muffler off

 

[angelo c]

Adjusting the valves on these 4mix motors is critical. They get wonky when out of adjustment and or they get hard starting when the cam lobe wears. I really hated the 4mix until I had a few apart...now i just mildly disapprove of them . They have such a "different" feel then 2strokes we all grew up with. But when using one for extended periods of time...I reach for them as the vibrations are more tolerable

 

[Mike C.]

Yes they are. Ones I’ve had to change were on units that the customer removed the guard. Or a loose backing plate that holds the compression release.
View attachment 248900

I'm probably showing my ignorance,but those notches on the "sprocket"so close to the teeth look like a weak point...

Are the 4-mix engines generally durable?I treat my customer's FS110 just like my old 2-strokes-I don't baby it at all.He didn't seem too pleased when I lost the blade nut(which I paid for(2) and travelled to get for free),I can just imagine how bad he'd freak if the engine came apart while I was using it.That's why I generally don't use other people's equipment.He decided to lay down the five c-notes for the Stihl when I said I was no longer going to do the job because my tired Shindaiwa was no longer up to it.These people always say,"Don't worry about it",but's it's amazing how their attitude changes when their equipment fails and they start seeing $$$$ signs.

 

[Mike C.]

Yes they are. Ones I’ve had to change were on units that the customer removed the guard. Or a loose backing plate that holds the compression release.
View attachment 248900

How does removing the guard damage the cam?

I've started the yearly chit-job at my friend's house where I use his FS110 and the first thing I noticed is that the guard was missing.He said his grandson had been using it and he likes to run the Stihl without a guard.The whole machine was covered in caked on grass,I almost wanted to so no thanks and toss it back in the garage.

And to think,when I get done with it at the end of my job,I take it home and completely clean it before turning it back in.I ought to tell the grandson to do it-spoiled little turd.

 

[weesa20]

How does removing the guard damage the cam?.

Allows the operator to run a really long string length and puts excessive stress on the whole system.

 

[Lcfd1124]

I've heard rumors that those engines have plastic cam lobes,is this true?

They do have plastic cams