Thomas Venditto
ArboristSite Operative
It's still doing it. If the key is sheared off, wouldn't the flywheel be turning? I mean, I'd notice it when rotating it (cover off) with the chain brake set.
Stihl 461 kicking back
- Thread starter Thomas Venditto
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Chain brake only stops the drum, if the saw isn't running the clutch would not engage the crankshaft.
Sometimes when the key shears it will get jammed between the crank and flywheel, basically you need to pull the flywheel to be sure.
Thomas Venditto
ArboristSite Operative
Thank you for the reply. You are of course, correct.
Question. Before I pull the flywheel, can I estimate TDC with a screwdriver in the plug hole and compare it with the flywheel position on the ignition module?
Question. Before I pull the flywheel, can I estimate TDC with a screwdriver in the plug hole and compare it with the flywheel position on the ignition module?
If the key is sheared, get another one or just line up the grooves is all you have to do. The key is for indexing, not holding it, the taper holds the flywheel once you tighten the nut. I have a few saws that have a sheared key that I lined up by eye and they work fine.
You can, but I don't know the firing spot for it? Old saws used to have a timing mark on the flywheel that pointed right at the magnetic coil , convenience!
I have had several saws that you had to push the decomp back every time you pulled it. Did not seem to be a big deal to me.
LarJea
ArboristSite Lurker
I replaced the coil on a neighbor's 044 years ago with a aftermarket coil that gave me the same problems, would yank the the rope handle out of my hands so I retarded the timing by grinding the treads off the coil hold down screws where it passed through the coil so that it would have enough movement to retard the timing. Not only was the saw easy to start but run as good as it did before.
billyboy
ArboristSite Operative
I have trouble with an 036 after it sets for a number of days, a week. I pull it over on choke and get no pop and then it’s flooded. Was told not to pull more than 3 times on choke. Two fifty cc saws start on 5 pulls or less so it isn’t the gas. If I start the 036 every day it’s not a problem.
What is the min./max clearance on the coil flywheel? My business cards run from .010 to .025. Does extra clearance retard timiing. Is it a no-no to file on the coil mounting holes to retard timing?
The 036 has good fuel , impulse, filter. Needle valve holds pressure. 170 psi. H
What is the min./max clearance on the coil flywheel? My business cards run from .010 to .025. Does extra clearance retard timiing. Is it a no-no to file on the coil mounting holes to retard timing?
The 036 has good fuel , impulse, filter. Needle valve holds pressure. 170 psi. H
I know this is an older thread, but we had a MS461 hydro locked this week. First time I remember with a chainsaw.
Happens regularly in two cycle blowers. And of course they yank it and spin the fan loose enough to be annoying.
Happens regularly in two cycle blowers. And of course they yank it and spin the fan loose enough to be annoying.
Pull the flywheel. Stihl says to rough up the tapers with a little valve grinding compound. Souring powder in a pinch (me, not Stihl).
I have had the same problem with a Jonsered 2050 and confirmed that it was NOT a timing issue. Timing at pull over speed was 23deg BYDC (same as a swapped coil from a similar problem free Jonsered) and that should not present a kickback when starting. Only conclusion I could come to was the problem might be related to excessive carbon build up so I gave up trying to figure it out and just retarded the timing by 5deg to 18deg BTDC. Problem went away and still seems to run normal at high rpm under load.
Beware when you start modifying the timing, you have to use a timing light to find out where you are before making any changes. Guessing and trial and error is not good. When you start relocating the position of the FW on the crank you will lose the relationship between it and the piston, so you will have to do the timing from the clutch side. You need a sector from a degree wheel (easy to make) and you have to find piston TDC accurately.
If you are modifying the timing to make a replacement coil work and the coil has way too much retard for starting purposes as compared to the existing coil, any advance you make to the timing at starting speed will also show up as the same amount of advance at top rpm. For stock chainsaws the maximum advance is 30deg, and your original coil is probably mounted to provide close to that, so if you advance the timing at starting speed by 5deg, you might be setting the high rpm by 35deg. Check with a timing light before doing any serious cutting or engine damage could result.
Beware when you start modifying the timing, you have to use a timing light to find out where you are before making any changes. Guessing and trial and error is not good. When you start relocating the position of the FW on the crank you will lose the relationship between it and the piston, so you will have to do the timing from the clutch side. You need a sector from a degree wheel (easy to make) and you have to find piston TDC accurately.
If you are modifying the timing to make a replacement coil work and the coil has way too much retard for starting purposes as compared to the existing coil, any advance you make to the timing at starting speed will also show up as the same amount of advance at top rpm. For stock chainsaws the maximum advance is 30deg, and your original coil is probably mounted to provide close to that, so if you advance the timing at starting speed by 5deg, you might be setting the high rpm by 35deg. Check with a timing light before doing any serious cutting or engine damage could result.
Anyone ever had the oil tank gasket fail and leak oil into the crankcase. OMG saw has some crazy compression when that happens usually the starter fails and breaks been there done that... 
Vapor pressure in the fuel is just too low. Once it's flooded your beating a dead horse. The case condensed all that fuel and you get hydrolocking just like a bad seat or needle in the carb loading the crankcase up with liquid then transfered to the cylinder. Had a saw do that last week. 72° on winter fuel blend. Changed to a higher octane and it was gone. Likely got much better fuel in it to cure the issue.
You ask and answered your own question you said if you started everyday. That tells me you are bypassing fuel through the carburetor and loading up the crankcase if it sits for 3 days
billyboy
ArboristSite Operative
The needle valve holds pressure. Could you explain what is happening?
Our trail crew has a Stihl 290 that was kicking back very badly.
This is all that I did to it:
Pressured and vacuumed tested fine.
Took carb apart and cleaned, put back together with existing gaskets.
Cleaned and reset plug gap.
Re-gapped coil to flywheel, it was off a little.
Fuel was the same that was in the tank.
Has been preforming well since.
Try the basics first.
This is all that I did to it:
Pressured and vacuumed tested fine.
Took carb apart and cleaned, put back together with existing gaskets.
Cleaned and reset plug gap.
Re-gapped coil to flywheel, it was off a little.
Fuel was the same that was in the tank.
Has been preforming well since.
Try the basics first.
The needle valve holds pressure IF the fuel vapor has not expanded beyond the top pop off. Find this alot this time of year with winter to summer fuel changes.
Lever setting inside the carburetor could be too high. See this regularly on 046/460, 044/440. This is why I pressure test the fuel hose and carburetor when I change a fuel filter in the shop. Tells you a lot in a minute.
And old fuel (over 90 days). If you don't think so, just see how many saws start up in the shop by changing the fuel. #1 issue.
Lever setting inside the carburetor could be too high. See this regularly on 046/460, 044/440. This is why I pressure test the fuel hose and carburetor when I change a fuel filter in the shop. Tells you a lot in a minute.
And old fuel (over 90 days). If you don't think so, just see how many saws start up in the shop by changing the fuel. #1 issue.
We need some clarification here, is the engine hydro locked or not? Easy to tell if it is, just remove the plug, turn the saw upside down and with ignition off, pull the engine over and see how much fuel comes out of the cylinder. It takes a LOT more than a few teaspoons of fuel to cause hydro lock. If the saw coughs and tries to jerk the pull cord out of your hand, that is NOT hydro lock, it's timing or some other issue. It's important to accurately describe the fault symptoms or you will be getting weird advise that has nothing to do with the problem.
Thomas Venditto
ArboristSite Operative
Because the handle either stops dead or more frequently pulls back, right out of your hand with incredible force. Feels like it's gonna break your finger. That thing hit my leg once and left a big bruise, even thru my insulated pants. The top of the saw has black marks on it from the rubber striking it. Until you have it happen to you, you can't imagine it. I have a bud at work with a 261 that is shelved for the same reason. Another has a 361 also shelved. Both of them are waiting on my fix, for theirs. Mine is a "home saw". There's is a work saw for the fire department. It HAS TO WORK when needed.
Time to diagnose and fix it. Go from the outside in. Start with fuel. Definitely check coil mounting and flywheel key. All you need is on here from posters. Go for it!
