Stihl 461 kicking back

[Thomas Venditto]

Sorry if I used the wrong terminology. When I attempt to start the saw, she locks up and pulls the starter cable out of my hand. The saw is a few years old with VERY low hours.
The decomp button pops up every pull.

Those who have experienced this know it's NO FUN.

TomJV

 

[Totembear]

Check the flywheel key, might be sheared off causing the flywheel to rotate on the crank.

 

[Gord404]

Or could be vapor locking because the carb not holding pressure and seeping into your crankcase

 

[user 122190]

Replace the decomp button. It should stay down til the saws fully starts. Should cost you less the $10.

 

[Squareground3691]

Either timing off some how or decomp valve like others have said assuming

 

[lone wolf]

Or could be vapor locking because the carb not holding pressure and seeping into your crankcase

Hydrolocking.

 

[Squareground3691]

Pull plug out hold throttle wide open pull over a several times then reinstall plug and try again

 

[cookies]

Decomps wear out and get weak also get carbon packed preventing full opening, the coil could also have lost its ability to retard timing below idle speed.

 

[Maintenance supervisor]

I've basically swapped all of my stihl decompression buttons over to Husqvarna. They have a larger hole in them and dont pop off mid start.
Excess fuel is probably the best answer as others have mentioned , I often store my saws with the decomp pushed in so the cylinder can breathe.

 

[trains]

Something simple to check with a low hr saw thats been left for a while, is a dried out, and stuck metering lever/ needle, thus the carb floods, and that hydro locks the piston in the cyld, as has already been mentioned several times, thought it worth just a bit of explaining rather than just saying.

As already mentioned, remove plug, pull over, check for fuel escaping to confirm/ wet plug etc.
Had a 660 that would do the same, sometimes it would hold pressure, ie tank would not leak into the engine via the carb leaking needle, other times it would leak into the engine and lock it when I tried to start it, really stings the fingers.

Simple check, has the fuel level in the fuel tank dropped since you last used it the day before ? for example.

 

[chainsawman53]

New ignition coil will fix that problem.
I used an after market for the MS 460. ( Ms 460 has no advanced ignition with high rpm and no rpm limiter but works fine )
Hope that helps,
Garry

 

[Gord404]

Hydrolocking.

Yes... was still half way thtough my morning wakup time

 

[JustaTreeGuy]

Sorry if I used the wrong terminology. When I attempt to start the saw, she locks up and pulls the starter cable out of my hand. The saw is a few years old with VERY low hours.
The decomp button pops up every pull.

Those who have experienced this know it's NO FUN.

TomJV

I have the same problem and agree, it's no fun. Pre-ignition is the most likely cause.
Early ignition causes the piston to fire before TDC and go backwards, jerking the pull rope out of your hand. Early ignition is likely caused by a misalignement of the flywheel magnets with the coil. Other less likely possibilites are a spark plug, carbon buildup or carburetor too lean.
I plan to start with changing the plug -- unlikely fix but easy; maybe I'll get lucky. Next will be to remove the flywheel cover and pull rope and check the flywheel: is the nut or flywheel loose and, with the brake on, does it move on the crankshaft. If it does that's the problem.
Next check clearance between the magnets and the pickup poles of the coil; the gap should be the thickness of a business card. I might try losening the screws on the coil and try moving it CCW to retard the timing a bit. Increasing the gap might also help.
If those don't fix it then it's time to pull the flywheel and check if the key is sheared or the groves on the flywheel or shaft are worn. This is a bit more work as it requires locking the piston at TDC, popping the flywheel loose, inspecting for damage and putting it back together.
If any of this works I'll let you know.

I've also heard of holding the decompress down while starting. One time I pulled the rope about 5 times in the OFF position. Then switched to start and it didn''t kickback. It started right up.

 

[TomW]

I have had problems with kickback when there was old gas in the saw. The problem went away when fresh gas got through its fuel system.

 

[lone wolf]

I have had problems with kickback when there was old gas in the saw. The problem went away when fresh gas got through its fuel system.

I wonder how many parts got replaced due to others to not checking this.

 

[purdyite]

New ignition coil will fix that problem.
I used an after market for the MS 460. ( Ms 460 has no advanced ignition with high rpm and no rpm limiter but works fine )
Hope that helps,
Garry

Plus one on the coil. Had a 291 that was doing that also--very painful trying to start. No problem with the new coil.

 

[TobbeR]

I have a MS660 that did this and after increasing clearance some between coil and flywheel it was ok.

 

[250R]

double post

 

[250R]

I've basically swapped all of my stihl decompression buttons over to Husqvarna. They have a larger hole in them and dont pop off mid start.
Excess fuel is probably the best answer as others have mentioned , I often store my saws with the decomp pushed in so the cylinder can breathe.

Whats the part number of the husky valve?

 

[Maintenance supervisor]

Part # 503 71 53-01