remove woodruff key carcass from flywheel?

[heyduke]

You can run a 371 with no key, just line it up and hit it with an impact. They wil L stay, it's the taper of the crank that truly holds the flywheel.

this is probably true for a saw that will live on the shelf in your garage. it will probably start and run fairly well for a little while. the timing will not be perfect. a deviation of a few thousandths of an inch at the crank is significant. also, if you use the saw regularly the timing may change. don't ask me how i know.

 

[BGE541]

this is probably true for a saw that will live on the shelf in your garage. it will probably start and run fairly well for a little while. the timing will not be perfect. a deviation of a few thousandths of an inch at the crank is significant. also, if you use the saw regularly the timing may change. don't ask me how i know.

So how does on advance timing it not alter the key? You have to be smarter then the flywheel... that's why I grind a notch in the flywheel and the crank so I know where "zero" is and go from there. The key is not designed to support the while set up, rather basic alignment, which often gets altered... I have built several 371/372 and build none "sit on the shelf" with no issues, I know other builders here do it the same way. Just my .02...

 

[ChoppyChoppy]

I can't imagine a few thou would matter much. I've had lawnmowers come in that still ran with the flywheel a good inch or more off after the key sheared. (Did run poorly though)

 

[old CB]

Doesn't the timing depend on the correct location of flywheel? I would think a degree or two off in one direction or the other would affect performance. The cost of a flywheel with the key to set correct spark timing seems like a small cost when averaged over the many hours of use.

But I'm a sawyer not a mechanic.

 

[heyduke]

So how does on advance timing it not alter the key? You have to be smarter then the flywheel... that's why I grind a notch in the flywheel and the crank so I know where "zero" is and go from there. The key is not designed to support the while set up, rather basic alignment, which often gets altered... I have built several 371/372 and build none "sit on the shelf" with no issues, I know other builders here do it the same way. Just my .02...

the best way to change ignition timing is by modifying the woodruff key. i have seen offset keys for sale that accomplish that. i have never seen verifiable evidence that changing the timing resulted in increased torque. most builders perform this mod to allow a saw to "spin up" more quickly (sound cooler). also, i appreciate your anecdotal claims regarding the longevity of your timing settings, but have you ever gone back after one of your saws has been run hard, in the field, for several hundred hours and checked to see if it was still the same? i have had saws come into my shop with sheared aluminum keys with a tight flywheel nut. i don't know what causes this, but suspect it is the chain brake being operated during high rpms. so yes, the flywheel can slip, even with an aluminum key.

 

[Derf]

This happened to a 372xp I had at the CT GTg and MattyO fixed it for me. The key is actually just a place holder- it doesn't do more than provide alignment for the flywheel. The nut holds it on tight enough with a friction fit that the key isn't necessary. He used a Dremel and ground out a slot in the flywheel where the cast-in key was. Then he used some copper wire (nomex?) to act as a key. Fixed my saw. He has a YouTube video on how to do it too.[emoji106]

 

[BGE541]

It's not rocket science... I have saws that production cutters use... done 20+ saws that way and never had an issue.

 

[buzz sawyer]

Just make sure both tapers are clean and oil free.

 

[BGE541]

Just make sure both tapers are clean and oil free.

Brake cleaner works well for me.

 

[buzz sawyer]

Yep, same thing. For proof that you don't need a key, my Mac Sp125C just has a taper for the clutch mount - no key. I'm sure there is more strain on it than any flywheel you'll run into.

 

[fearofpavement]

I agree with others that the saw can be assembled with no flywheel key. The key is for alignment purposes only. I use a sharpie to mark the flywheel and assemble them. Never had an issue.

 

[heyduke]

It's not rocket science... I have saws that production cutters use... done 20+ saws that way and never had an issue.

i certainly respect your skill and experience but i've worked on saw that arborists and firewood guys use. and i've found sheared keys. if it's an integral aluminum key, i order up a new flywheel.

Yep, same thing. For proof that you don't need a key, my Mac Sp125C just has a taper for the clutch mount - no key. I'm sure there is more strain on it than any flywheel you'll run into.

I agree with others that the saw can be assembled with no flywheel key. The key is for alignment purposes only. I use a sharpie to mark the flywheel and assemble them. Never had an issue.

so if tapered shafts don't slip, why were you working in there? was there a sheared key? i know you can slap a new piston in an old 029 and use the old flywheel with a toasted key, send it out the door for a couple of benjamins, but did you really check the timing after it cut 20 cords? i've known a lot of mechanics who never replace as many fasteners as they removed, but i do. it's my values and my craftmanship. also, i don't leave the key out to advance ignition timing because i think that's snake oil 90% of the time. prove me wrong with real hard data (not anecdotes) and i'll eat crow, done that before. sometimes i think that 75% of the work i see on my bench is due to someone else's sloppy work or ignorance. not trying to bust anybody's chops. you do it your way. i'll do it frank's way... er my way.

 

[old CB]

$32 for a used OEM flywheel shipped to my door. Installed, 24 ft. lbs. on the nut--this one shouldn't fly off. Saw is back in service, and I'll never wonder whether the timing is right.

CB

 

[heyduke]

$32 for a used OEM flywheel shipped to my door. Installed, 24 ft. lbs. on the nut--this one shouldn't fly off. Saw is back in service, and I'll never wonder whether the timing is right.

CB

it makes sense to me. you don't want a saw that might be good when you show up to work. you want a saw that you know will make it thru the day. i buy flywheels off of ebay and so far i haven't been disappointed. i'd be interested to know where you found the torque specification, 24 ft lbs. someone was writing earlier that he just torqued his down with an impact wrench. he didn't offer any details. it could have been a home depot 18vdc or a 1/2 inch pneumatic, 20 ft. lbs or 120 ft. lbs.

i bought my first saw in the 1980's, a husky 61. i still have it (unlike any of the women since then) and it works better than the day i bought it, 160psi at 6000 ft. elevation. the only field mods are a rim sprocket clutch and a 272 chain brake. which is funny because a lot of hombres here think those old chain brakes are cool (or maybe look cool) they were garbage and are unsafe. except for those two things, i've kept the saw totally stock and 35 years later it feels right.

 

[old CB]

I have a repair manual: "Chain Saw." It's a 1998 edition, so I just took the spec. for a 272--pretty sure the 371 and 372 will be similar. The torque for flywheel nut was 22--29 ft. lbs. and I set my wrench for 24.

You're at 6000 feet elevation--I live at 6400' and work from here up to 8,000' (sometimes higher). Right now I'm having fits with the 550xp autotune I bought last year for limbing and small trees. (The 372 is my everyday go-to saw, the 371 is a backup.) That thing starts okay cold, but once it's running, if you set it down for 5 minutes it's absolute hell getting it running again. It will fire, then hesitate and die. You spend several minutes fussing with it before it will run right. A neighbor asked for a recommendation last year, and they bought the same saw after I said I'd just bought this, and theirs acts exactly the same.

I took it to my dealer last week thinking they could reset or adjust something. But the mechanic said they've been having trouble with autotune at our elevation--and they're only 5400' in town. Said he could look at it if I drop it off for a while, but it's my busy season and I don't have 2 weeks to be without it. Altho I'm getting to the point where I might take it in, 'cause it's half useless to me.

 

[Poleman]

The flywheel can be used with out the key. I intentionally grind them off when unlimiting a Dolmar 7900/7910 style saw. It's the compression on the taper that holds it tight not the key....the key will help if the nuts loose though...until it shears. If there is still a problem I put a little 518 on the crank shaft on installation, once set it acts to hold the flywheel stable.
Mark your crank end for TDC and use a sharp pointed punch and tap a mark where the key is located on the flywheel. You know have indexing marks to go by. If once installed the saw starts and runs good you pretty close and it's usable. If the saw is boggy with bad throttle response the timing is retarted and needs to be advanced....a little. A little goes a long way here, a little change at the crank is a bigger change at the outer ring of the flywheel where the magnets trip the coil. It's mostly patience and some trial and error if you don't get it the first time. Remember to punch mark the sweet spot once found for future reference. You can mark the crank end also with a flat punch to scribe a small line in it for a more permanent index mark.

 

[heyduke]

I have a repair manual: "Chain Saw." It's a 1998 edition, so I just took the spec. for a 272--pretty sure the 371 and 372 will be similar. The torque for flywheel nut was 22--29 ft. lbs. and I set my wrench for 24.

You're at 6000 feet elevation--I live at 6400' and work from here up to 8,000' (sometimes higher). Right now I'm having fits with the 550xp autotune I bought last year for limbing and small trees. (The 372 is my everyday go-to saw, the 371 is a backup.) That thing starts okay cold, but once it's running, if you set it down for 5 minutes it's absolute hell getting it running again. It will fire, then hesitate and die. You spend several minutes fussing with it before it will run right. A neighbor asked for a recommendation last year, and they bought the same saw after I said I'd just bought this, and theirs acts exactly the same.

I took it to my dealer last week thinking they could reset or adjust something. But the mechanic said they've been having trouble with autotune at our elevation--and they're only 5400' in town. Said he could look at it if I drop it off for a while, but it's my busy season and I don't have 2 weeks to be without it. Altho I'm getting to the point where I might take it in, 'cause it's half useless to me.

i have no use for auto tune in any of it's flavors. several years ago there was a guy on here who was working at 9000. i think he was down in the gila. he bought a new 372 at (if my memory is correct) and couldn't get it to work. the dealer couldn't get it to work either. i don't like black boxes with secret stuff inside. i work from 5000, down in the bosque, by the rio grande, up to 9000 in the mountains between here and colorado. my place varies from 6000 to maybe 6500. my go-to saws are a 575 and some big-bore makitas. sometimes i'll take a 385 as a backup saw or a long bar. they all work really well and reliably. we call a saw that won't work when it's hot a "lazy groundman," because you can't get it to work after lunch.

 

[Poleman]

We have flat land low altitude Kansas crew working in our area and all their auto tunes won't run...even after being reset. The GF and the crews aren't real happy about it. We're only 3500 to 6000/6500 ft in elevation and their having fits with equipment.
Call me old school but I hate "black boxes" too.....

 

[old CB]

Yep, my older saws start and run fine when I have a tuning screwdriver.

I just heard from a guy on another thread that I've been starting my 550 wrong when it's hot. I need to push the lever to choke position, then back off choke so I've got a fast idle setting WITHOUT choke. Can't wait to try it. Headed out the door to work now.

 

[heyduke]

We have flat land low altitude Kansas crew working in our area and all their auto tunes won't run...even after being reset. The GF and the crews aren't real happy about it. We're only 3500 to 6000/6500 ft in elevation and their having fits with equipment.
Call me old school but I hate "black boxes" too.....

i need a saw that you can repair on your tailgate, and if that won't get it then back in the shop. we don't have a husqvarna dealer within 200 miles of here. i think there are only on or two in our entire state. so you're on your own, which is just fine. the best dealer close to me is the dolmar guy but he's up in the air with all the makita/dolmar rebranding issues and their recent deteriation of parts supply service. pretty much any town with a population of 2k or more has a stihl dealer. they vary in quality from mediocre to bad. but they have great ads.

yeah, we've beat that woodruff key issue to a pulp in this thread. i'm still in the pro-key minority. i've seen them slip, probably due to chainbrake operation. i've seen saws with poor timing because a guy who's great operating a saw isn't necessarily a highly skilled mechanic, he's lucky if he remembers the 2stroke oil. if you're installing a nonstandard module that doesn't match your flywheel, you don't have a lot of choice though. i'd wager that i could take a keyless flywheel of the shelf and put it on a 70cc saw, torque it to 25ft/lbs and make it slip.