Husky 357xp flywheel key

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Nothing wrong with filing the key, it's only there to provide proper alignment in the factory, it's the jam fit of the flywheel on the taper end of the crank and correct torque of the nut that keeps it in place. If you are going to modify the timing, it's important to know what it is before you start. Most saws will already have the timing set for max advance which is 28-30 deg BTDC and if you advance it more than that, you will achieve nothing except possible engine damage and a lot of kickback when starting. You need a timing light and know how to use it before doing any timing modification.
 
Nothing wrong with filing the key, it's only there to provide proper alignment in the factory, it's the jam fit of the flywheel on the taper end of the crank and correct torque of the nut that keeps it in place. If you are going to modify the timing, it's important to know what it is before you start. Most saws will already have the timing set for max advance which is 28-30 deg BTDC and if you advance it more than that, you will achieve nothing except possible engine damage and a lot of kickback when starting. You need a timing light and know how to use it before doing any timing modification.
Some engines like more advanced, some do not. You just have to try it and see.
There is no such thing as max advance. You can advance the timing as much as you want, but keep in mind as you do the piston crown temp and sparkplug electrode are getting hotter and hotter. At some point you run into pre ignition or detonation and its game over.
 
I have a decent understanding how ignition timing works in general. At least in car engines not really in a chainsaw. I was more curious if anyone has advanced the timing on a 357xp (or any of the similar models like a 359) and if it made any difference and if it was worth messing with.
 
I would be very cautious about doing this. Especially of the 357 flywheel is no longer available.
Yeah that's why I was asking. I didn't realize the key was integral in the flywheel and considering a flywheel for it is about $220.00 I'm a little reticent to try it lol. If it was a key that would be different. Just finished doing the metal band swap on this guy, new impulse, reringed the piston, cleaned up the piston crown and cylinder, deleted the carb limiters, removed the base gasket and piped it. Thing rips, love it. Goes nicely with my 346xp.
 
Some engines like more advanced, some do not. You just have to try it and see.
There is no such thing as max advance. You can advance the timing as much as you want, but keep in mind as you do the piston crown temp and sparkplug electrode are getting hotter and hotter. At some point you run into pre ignition or detonation and its game over.
I don't recall seeing any stock saw that is running more than 30 deg and I have never pushed it beyond this. What is the maximum advance that you have used and what criterion did you use to determine it was an improvement in performance? I'm not crazy about advancing the timing until engine damage occurs so you will know that was too much.
 
I don't recall seeing any stock saw that is running more than 30 deg and I have never pushed it beyond this. What is the maximum advance that you have used and what criterion did you use to determine it was an improvement in performance? I'm not crazy about advancing the timing until engine damage occurs so you will know that was too much.
Cr500 of certain years had an advance curve such that the peak was 33 degrees stock.
Can't speak to saws as I have never looked at the curves for them.
I am not crazy about advancing either because it takes away some insurance and it also can make the power curve more narrow.
However some saws with poorly designed ports like the Stihl 260 need it.
 
I did a timing advance on a 359, it liked it and runs better.
I took enough off the key to advance it half a cooling fin.
There's a used flywheel on fleabay for cheap that I might grab and try it. I'm just curious to see if it makes a difference. Right now the saw is an animal after the few changes I've made, very happy with it.
 
I don't screw with anything that is prone to harsh pull-back. That'll tell you it's already advanced enough. A couple of my examples are jonsered 590's and early 262xp's (no experience with the later ones). They are wee saws that can hurt your hand a bit if you don't pull them with authority.

Hilariously (or perhaps dangerously) a two stroke will run backwards with "over the top" advance.

I'm kinda diggin' spring-assist starters at times these days..
 
The 357 is a factory hot rod. I also don't mess with factory hotrods, as they run good enough for me as-is. Nice, clean ones are a bit of a collector saw so imo, should be left alone. But each to his own. The 357 is a beautiful saw. To look at and to run. I wish I had one. Maybe I should start keepin' an eye out again.

Oh, and in case you are not aware, make sure yours has the steel clamp on the carb-to-cylinder boot. A ton of the early 357's burned themselves up because of a failed plastic clamp. Lots of sawhands reluctantly turned to the 359 which was less problematic, even with the plastic clamp 🤷‍♂️
 
Maybe helpful for you.... I purchased a flywheel from H & L supply (aftermarket) for one of my Husqvarna 350 chainsaws after accidentally shearing the molded key for the OE flywheel. I ran maybe 5-10 tanks of fuel through the saw , but it just didn't seem to have the snap and gumption I remembered. I then purchased a very used OE flywheel from ebay and installed it. Bam ! The snap and power came right back to what I remembered. I never measured the timing of either flywheel, but am fairly confident the timing tolerance on the aftermarket flywheel I used was very safe = delayed.
 
Maybe helpful for you.... I purchased a flywheel from H & L supply (aftermarket) for one of my Husqvarna 350 chainsaws after accidentally shearing the molded key for the OE flywheel. I ran maybe 5-10 tanks of fuel through the saw , but it just didn't seem to have the snap and gumption I remembered. I then purchased a very used OE flywheel from ebay and installed it. Bam ! The snap and power came right back to what I remembered. I never measured the timing of either flywheel, but am fairly confident the timing tolerance on the aftermarket flywheel I used was very safe = delayed.
Interesting. I usually steer clear of knockoff parts. Too many bad experiences. I might snag a used oem flywheel of ebay and experiment a bit.
 
There's a used flywheel on fleabay for cheap that I might grab and try it. I'm just curious to see if it makes a difference. Right now the saw is an animal after the few changes I've made, very happy with it.
You can undo a timing advance easily if it makes it kick back or doesnt help.
You file the built in key down on one side only, now you have two different timing settings. If you twist the flywheel ahead while installing it you advance the timing, if you twist the flywheel the other way you're at stock timing.
 

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