Stihl, FS55R, New Coil andCarb, Won't Start

[S Haase]

Have a FS55R that gradually became harder to start. (8 yrs old with light use)
Good compression, Good switch, Fresh Gas…
Clean spark arrestor and Muffler… No Start
New Plug…(Old, NKG BPMR7A) (New, Champion CJ6Y), Both Gap .025…No Start
Didn’t feel it had enough spark so replaced the coil (Stihl 4140-400-1308) gaped @ .012 with feelers gauge.
No start
Removed the flywheel and there was a little slop in the key. Maybe 1/16 at the outside diameter of the Flywheel. Centered and LockTighted (High Strength) onto the shaft. Got a little sputter, That’s all.
Put on a new Carburator (Stihl 4140-120-0619) :
Still won’t start.
If I set the plug over the open port, and spin the shaft with my D/C drill (CW) it did ignite the gas in the cylinder. I am just assuming the spark is good.
Note: the old carb had #’s S153 and S48B on the body.
The new Carb. Had #’s S186D, 4140/19D and 647A on the body.
WHAT AM I MISSING?
Thinking of taking the Flywheel off an shifting it all the way CCW LockTighting (set overnight) it and trying it again.

 

[The Specialist]

Hi

I read your problem, and you need to determine a few things first. Remove the Exhaust and look in the port. If you see "barcodes" your engine is shot!! You should not see and lines on the piston at all! If the piston looks good then your engine is OK. The one thing that you did miss though is the fuel filter in the tank. These get plugged with water from the moisture in the air. Replace your fuel filter with part number 0000 350 3502. You can't blow them out with a compressor!!!! Ill explain how all of this works! From the fuel cap to the spark plug, this system is a pressurized system. If the fuel filter is blocked, fuel is not getting through. Most people think that the carb is the fault. The carb only controls this pressure. To do a simple test, remove the lower fuel line from the carb. The fuel should come shooting out from the tank. If it doesn't, your fuel filter is blocked! let me know how you make out and you can also contact me at dvata@yahoo.com. I am a stihl Master Service Technician!!

 

[Martepm]

"S", did you ever figure out what went wrong?
I have the same problem and it's still ongoing. Replaced coil, carb, fuel lines & filter & flywheel. Contacted "T" & he was nice enough to give some tips. Flywheel key was sheared off. With new wheel, same problem. Fuel tank is pressurizing.
I'll get sputters spinning motor with elect drill but that is it.
I know its an old post but hoping you remember as I have done exactly the same process & getting same results on my FS55RC.
This is driving me NUTS!
Thx...

 

[Fish]

It doesn't take much.
It is the main reason I had selling flywheels, they are easily resheared.

 

[Martepm]

Thx fish.
Not to argue, but wheel only goes on one way & can't be adjusted as you know. When I put new one on it slid on without any side-side movement. After checking fitment, used Loctite 603 & let it set for days to dry. I find it hard to believe it moved, if you know what I mean. I Loctite'd the clutch screw too. Couldn't get that off yesterday. Looks as though the only way to get clutch & wheel off is by heating with torch. Then what problems will that produce?!?

I just now rechecked piston movement at TDC. 1st pic is when piston stops moving upward at TDC. 2nd pic is when piston just starts moving downward after TDC. Much like your pic.
Again, without trying to argue, it looks perfect to me. Yesterday put on just carb & tank (hanging). Wouldn't fire. Put thumb over carb & got mist out of exhaust while using elect motor to spin. After 10-15 sec, started firing but wouldn't run. Couldn't get anything better than that so put everything down & walked away for the day. Exhaust port was wet so think it got too much fuel during this test thus the 10-15 sec delay in firing.
I know I'm right there, just something is amiss.

 

[StarTech]

If you turning the direction of the arrow you are turning the wrong way.

 

[Martepm]

Pulls up on left side...

 

[Martepm]

OOOPS! That is opposite looking at f/wheel side...DUH!
But still good, spinning motor is clockwise direction on the other side.

 

[Martepm]

Updated TDC movement, turning c/clockwise..
It looks even closer to your pic now.

 

[Khub]

Curious if you ever figured this out? I have exact same issue, and I’m at a loss of what else to try?