The speed limiter on the MS461 can be a nuisance at times. >:(
#. Your old tach will not work for carb tune-ups
#. If you are used to setting your carb to any rpm above 13,500, its difficult.
In the MS461 the rpm sensing is done by the 3rd pole of the ignition module, which differentiates the 461(ignition module) from the 2 pole unit on the 460.
So, I just cut off the 3rd pole! Okay, not chopped off completely, but trimmed off enough so that this pole will not pick up any working magnetic impulses from the flywheel
And it works. 8)
I held the pole compressed with a pair of pliers that had wet cotton waste on the jaws.This prevented the iron plates from transferring heat onto the coil inside while I used a hand held cutter.
Heat transfer will sometimes cause the copper winding to snap from expansion.
(https://forestryforum.com/gallery/albums/userpics/15459/01.JPG)
Thanks Joe, seems theirs a way around every problem they throw at us. Frank C.
Another innovative tip, Joe! :) :) :)
Joe how does the saw run with the unlimited coil? I know the stock 461 coil has a pretty good advance to it, did you advance the flywheel any to compensate? You probably won't notice any difference on a work saw.
Andre,
The MS460 has what you might term as an 'unlimited coil'
I dont thing there is any difference between the basic ignition timings of a 460 and 461 .
No ,I did not advance the flywheel.I only did the mod on the coil.
Regarding the noticeable difference on a work saw, maybe you have a point for saws running with longer bars.
But with 18 and 20" bars that speed comes up fast.
Agreed that rpm in the wood is much lower (round about 9800rpm or so) but when going through wood of small diameter, that extra rpm matters a lot.
The cut off by the limiter feels something similar to tripping a person who is running fast.
If you fit a 460 coil in a 461 you will understand much better what I am trying to explain.
If I am not mistaken, the speed limiter is there because of regulations, to ensure the user cannot tune to dangerously high rpms.
This picture will explain it better.
The MS460 had a 2 pole coil.
The MS461 has a 3 pole coil.
The 3rd pole's function is only to read magnetic impulses (via fancy electronics I think), so that when impulses cross 13500/minute.When the impulse reading is 13500/minute, the saw is running at 13500 rpm. Beyond this rpm the (say 13550) every other ignition spark is cut so that the rpm is limited to 13500.
For many users this kind of limiting acts as a leash on the potential of the saw.
(https://forestryforum.com/gallery/albums/userpics/15459/coils.JPG)
Fantastic info!
Thanks alot!
7
Very interesting to say the least! Wonder if the deal is similar on my Dolmar/Makita 6400?
Hu
I understand, I'm quite familiar with limited coils and how they cut ignition. What I was referring to is the 461 coil advances the timing at speed for better power, and retards the timing at idle for easier starting. Limited coils are there more for durability than anything else. Saws have had rev limiting of some type since they've existed, and doesn't effect performance as long as you have the carb tuned correctly.
This video shows how the 461's coil advances timing. Like I said you likely won't notice a difference. :)
http://youtu.be/SDrmLhi4isA
Andre,
Thanks a ton for your post!
What I now realise is that other than removing the speed limiter, by trimming the 3rd pole I have also stopped the ignition advance! ;D
This info is great! Because the MS461 crankshaft failure here could be because of the timing advance. Not a good thing for our below average fuel.
So, I know also know that I am actually killing two birds with one stone by trimming the third pole. 8)
Once again, great useful info for me and I am really grateful! smiley_clapping
Joe
Quote from: shootingarts on January 02, 2014, 03:56:06 PM
Very interesting to say the least! Wonder if the deal is similar on my Dolmar/Makita 6400?
Hu
I dont think its a similar set up on the Dolmar/Makita. The earlier coils and the present coils (like Huskies) have the same location, without any change.Plus they are 2 pole types.
I am not an electronic expert, but what I think happens is that when impulses(rpm) cross a set limit, a thyristor or scr shorts out the current thus controlling the rpm.This is what happens in some Stihl brushcutter and cut-off saw coils.
Like I said I am no expert in electronics, this is just a personal theory
Joe
You don't need three poles to make the coils limited or have timing advance. The Dolmars, and newer husky coils are limited, and some have advance as well. Husky's normally had more advance than the Stihl anyway, but as you can see that's changing with new Stihl models. The newer stihl also have quad transfer, this improves power and efficiency. Case stuffers don't hurt either.
smiley_beertoast
Andre.
do the 461 flywheels have the extra poles ?
Quote from: splitpost on January 03, 2014, 02:17:52 AM
do the 461 flywheels have the extra poles ?
No. They are the same two pole flywheels as those that come on the 460.
Both saws use the same flywheel.
cool,i was just thinking that if it had the extra pole it maybe swapped for an earlier version ,to overcome the limiter ,seems like the coil mod or complete coil swap is the way to go smiley_thumbsup
Quote from: splitpost on January 03, 2014, 04:46:20 PM
cool,i was just thinking that if it had the extra pole it maybe swapped for an earlier version ,to overcome the limiter ,seems like the coil mod or complete coil swap is the way to go smiley_thumbsup
smiley_headscratch
That's right
smiley_thumbsup
Good job Joe, thanks for the heads up on the third pole.
So from what I'm seeing here, the best thing to do is remove that third pole? Is there anything else besides that? The limited coil I think made me believe it was four stroking when really it wasn't.
Quote from: 4x4American on August 08, 2014, 09:09:30 PM
So from what I'm seeing here, the best thing to do is remove that third pole? Is there anything else besides that? The limited coil I think made me believe it was four stroking when really it wasn't.
A rev limited coil can sound like it's "4 stroking" under no load, free revs, thus making tuning difficult. Best way to properly tune the high speed on a saw with a rev limited coil, IMO, is to do it in the cut- tune so the saw cleans up the 4 stroke sound under load, but when you let up it's 4 stroking :)
This doesn't mean fiddling with the screwdriver in one hand while trying to run the saw with the other! Start pig rich and make small adjustments to the H jet between your test cuts.
Sorry, can't speak to what is "best" to do with the coil on the 461, never seen one...
Thanks. I opened up the muff hole a bit today on the ol girl. Now just trying to tune her in. Hard for me to figure out whether its strokin or bouncing off rev limiter.
If I have her WOT in the wood, and then pull out to listen, it'll rev up fast and I'm not sure if that's rev limiter or strokin. Is it better to be more 13/16 or 5/8 throttle than WOT?
Also, is there carb limiters on the 461? If there is, looks like it might be a pita to fix em.
Thanks yawl!
If you're using a tach for H adjustment, you're really into wishful thinking. Before mfgs encouraged laziness with that kludge, they said "adjust H for max speed under load.".
Exactly what Auto-tune does, for example. Going much beyond the power peak is just flogging a mule.
I've seen a few competent techs do the tach-tuning thing and get the mixture way rich. (They insisted on their righteousness all the while.) Easily remedied, though. Excessive richness can do long-term damage. Just think of little black diamonds being grown in the chamber, then shed.
Takes a few minutes longer, and is messier, to do it right. IMHO, well worth it.
It's helpful to look at plug color after some full-load running.
I don't own a tach and never will, saws should be adjusted to where the cut the fastest in bigger wood and that won't be lean or rich. Steve
So how's that 461 running? I've been thinking of de-limiting mine, but am tentative. Have you had any experience taking the carb limiters out?
4x4 - the "carb limiters" are a different thing than the speed limiters. Carb limiters affect your ability to adjust the mixture, and are easy to get out or modify.
I know, i asked about the carb limiters because the stihl's have them inside the carbs on the new ones and are harder to remove. for example on my husky 346 the carb limiters are plastic and on the outside and easy to remove. the carb limiters on my stihl 362 are inside the carb and from what I've read aren't as simple to take out, but I've never tried either. I haven't taken a look at how the ones in the 461 are in there, but I would think they're built into the carb. I modded the muffler on the 461 and want to fatten up the mixture a hair more, but the limiters dont allow it. The spark plug color indicates that it's fine, but when it comes summer time who knows what that will do to it.
I wouldn't have asked if he had any experience taking out the carb limiters if I thought they were the same thing as the limited coil, because this thread shows his experiences ;D
OK. I haven't seen the new Stihl limiters. I guess in another couple of years when everyone has switched to auto-tune saws, this will all be moot.
Quote from: 4x4American on January 13, 2015, 03:02:15 PM
So how's that 461 running? I've been thinking of de-limiting mine, but am tentative. Have you had any experience taking the carb limiters out?
These pictures should give you the required 'How-To-Do-It' info
(https://forestryforum.com/gallery/albums/userpics/15459/01.jpg)
(https://forestryforum.com/gallery/albums/userpics/15459/02.jpg)
(https://forestryforum.com/gallery/albums/userpics/15459/03.jpg)
BTW
I started this topic in Jan 2014. Since then I had been experimenting further to simplify the coil mod. I had started a new topic on a simpler method to do the 'de-limiting' with a video uploaded to youtube. I have modded more than 50 461s using this latest method with very good results. Though the video makes no mention of it (wanted to keep it simple there ) additionally to go the whole hog on the mod, I also replace the standard muffler cover with a 460 magnum cover, replace the standard 0.68 fixed jet with the 0.70 jet of the older HD14 carb of the 046 and then free the limiter caps as shown above to tune the carb for the change in the muffler and jet size. Andyshine77's post on this thread with the youtube link was what told me that the 461 coil also has an ignition timing advance and I found this was the actual problem to my local 461 users. So, though I lack the tools for confirming it, the wide gap at the 3rd pole eliminates the ignition timing advance and helped the local users get a 461 that they found more acceptable because it now seemed more similar to the 460 that they were used to.
Thanks for the detailed reply, Joe!
So I have a few questions on de-limiting the ms 461, I know it would make it a lot easier to tune thats a fact, but I've heard with this saw it adjusts the timing for some reason or another and also when its cutting in the wood it maintains a higher RPM while this pole is active does anybody know anything about this? you could get a higher overall RPM yea but if it is lower when cutting then it doesn't matter to me I'd rather be cutting faster than anything else.
TLDR: does the 3rd pole do anything else besides limit the top end RPM of 13,500 that I might like to keep?
Quote from: Wildman Ben on November 18, 2015, 05:56:42 PM
......................
TLDR: does the 3rd pole do anything else besides limit the top end RPM of 13,500 that I might like to keep?
If you read back on this thread you will find a post by Andyshine77 where he has given YouTube link. In the video the uploader has checked and found that other than limiting rpm at 13500, the third pole also advances the ignition timing. This maybe good for most applications, but in applications here with poor fuel and inexperienced users who are yet to know how to file a chain, it is much safer to eliminate the ignition advance, we faced a very high number of crankshaft burnouts. With the elimination of the third pole or a coil swap, we avoid this.
This recent thread too might be of interest to you.
https://forestryforum.com/board/index.php/topic,86302.0.html (https://forestryforum.com/board/index.php/topic,86302.0.html)
Post Script: The overall higher rpm under load is not only because of the ignition timing advance. The exhaust stratification design in the 461 results in much better torque so rpm drop under load is at a minimum. Plus stratification saves 20 - 25% fuel.
I'd think you'd lose quite bit of power without the timing advance. Those tabs on the limiter caps grind off in 2 seconds on a bench grinder . Echo saws advance the timing 30° from start to full rpm , sure wouldn't want to be without that. Steve
Losing 30 degrees of advance is a lot - you'll lose some power at higher RPMs without it. On the other hand, I've heard the more aggressive you are with the timing advance, the less tolerant the engine is of marginal fuel or "less than optimal" tuning. If fuel quality is a concern, maybe it's worth the trade-off?
Okay well I have good fuel and know how to sharpen a chain properly, is it nicer to keep that 3rd pole for the ignition advance then? I don't know anything about ignition timing / advance or how it works. I like the idea of taking away that 3rd pole mostly for tuning purposes, I find it difficult to tune in the cut. but if the ignition advance is a big plus I will leave it where it is.
A little bit about me and my saw, I run this saw (ms 461) with a 28" bar, I have switched the muffler to a dual port and removed the carb tuning limiters. I have good fuel thats payed for by company and am pretty experienced with the saw and maintanence, cutting production wood up here so the faster I cut the more money I make.
There are others on here far more knowledgeable than I about saw tuning and power, However, I believe if you are looking for the best performance, you do NOT want to disable the ignition timing advance.
As you noted, tuning without a rev limiter is easier. However, you would likely not see any improvement in performance even if you could disable the rev limit without disabling the ignition advance. The rev limiter is typically a factor when operating at full throttle out of the cut. Under load, your saw should not be approaching the rev limit, and that is typically not where you see the max power anyway. (NOTE: if you are running a highly modified race saw, the above may not apply, but from your description, that's not what you are running.)
And now, for the guys who really know what they are talking about in this regard, please jump in and correct me if I've got it wrong.
Watch the video. That MS461 advances from 8 degrees at idle to 16 degrees or so. A stock MS360 which he swapped the coil off of is fixed at 12 degrees.
So, it is not like it has no advance at all.
yea that 360 coil would be nice to have to swap out. I assume then if you remove that 3rd pole on the 461 that the timing would stay down at 8 degrees? which is super low
@joe did you trim the flywheel at all to try and get a more moderate timing after removing that 3rd pole?
Quote from: Wildman Ben on November 20, 2015, 03:35:07 PM
@joe did you trim the flywheel at all to try and get a more moderate timing after removing that 3rd pole?
No, I never touched the flywheel.
BTW, I would go with the 460 coil for a coil swap. The 360 flywheel seems to be a bit smaller in diameter than the 460/461 flywheel.
A good way to tell you are close with your tune is "reading the plug." You want a nice brown colored spark plug after some good use. Greye or white is lean, black or real dark is too rich. As for in the cut, if you have a nice big diameter log have a helper hold it WOT in the cut while you fine tune the carb
;)
I know this thread is quite old, but i followed the steps outlined here in order to "de-limit" the MS461 coil and have not been successful. First i tried making the gap from the 3rd pole larger, next I removed the 3rd pole altogether by cutting it away. The way I know these modifications didn't work is that I tested it with a tach. When it bounced off the limiter the tach started jump all over the place until it returned back to normal RPM levels. Without another coil and spending significant $$ to get a replacement one from the MS460, are there any other tips on how to successfully remove rev the limiter?
Quote from: 4x4American on January 14, 2015, 11:02:17 AM
I know, i asked about the carb limiters because the stihl's have them inside the carbs on the new ones and are harder to remove. for example on my husky 346 the carb limiters are plastic and on the outside and easy to remove. the carb limiters on my stihl 362 are inside the carb and from what I've read aren't as simple to take out, but I've never tried either. I haven't taken a look at how the ones in the 461 are in there, but I would think they're built into the carb. I modded the muffler on the 461 and want to fatten up the mixture a hair more, but the limiters dont allow it. The spark plug color indicates that it's fine, but when it comes summer time who knows what that will do to it.
Warmer weather will make it run richer so you should be good. Steve
Lot's of good info in this 4 year old thread. Only thing I can add is buy a good used Stihl 046 Magnum....Great old reliable power houses.
I got a project saw on my work bench at the moment. I took my old 1986 Stihl 064AV race saw out of retirement. I'm going to swap out it's raced ported cylinder with 084 carb for a 1995 066 P/C with the first year decomp valve.
I'll then have a real lightweight 90cc powerhouse for my tree service.
This first year 85cc 064AV at 14.1 lbs is lighter then the much newer 77cc MS460.
I'll have my 1992 066 Mag Arctic for backup.
Quote from: gowanus2015 on March 10, 2018, 04:24:58 PM
I know this thread is quite old, but i followed the steps outlined here in order to "de-limit" the MS461 coil and have not been successful. First i tried making the gap from the 3rd pole larger, next I removed the 3rd pole altogether by cutting it away. The way I know these modifications didn't work is that I tested it with a tach. When it bounced off the limiter the tach started jump all over the place until it returned back to normal RPM levels. Without another coil and spending significant $$ to get a replacement one from the MS460, are there any other tips on how to successfully remove rev the limiter?
If the tach reading is jumping at 13500+ rpm that third pole is still picking up magnetic impulses enough to limit the engine speed. That is strange. If that 3rd pole is trimmed off to leave a 3 -5mm gap it should not pick up impulses. Most of them stop getting impulses when the air gap at the 3rd pole is widened. In that case the only other option is to use a two pole coil. The ones from the 290/390/360/460/660...they are all suitable, with alteration of the length of the ignition lead. Or just swap the lead from your 461 coil.
Quote from: joe_indi on March 12, 2018, 09:06:57 PM
Quote from: gowanus2015 on March 10, 2018, 04:24:58 PM
I know this thread is quite old, but i followed the steps outlined here in order to "de-limit" the MS461 coil and have not been successful. First i tried making the gap from the 3rd pole larger, next I removed the 3rd pole altogether by cutting it away. The way I know these modifications didn't work is that I tested it with a tach. When it bounced off the limiter the tach started jump all over the place until it returned back to normal RPM levels. Without another coil and spending significant $$ to get a replacement one from the MS460, are there any other tips on how to successfully remove rev the limiter?
If the tach reading is jumping at 13500+ rpm that third pole is still picking up magnetic impulses enough to limit the engine speed. That is strange. If that 3rd pole is trimmed off to leave a 3 -5mm gap it should not pick up impulses. Most of them stop getting impulses when the air gap at the 3rd pole is widened. In that case the only other option is to use a two pole coil. The ones from the 290/390/360/460/660...they are all suitable, with alteration of the length of the ignition lead. Or just swap the lead from your 461 coil.
I guess 2 pole is the only way to go then. Thanks!
UPDATE:
As Joe_Indi suggested I ended up getting a cheap used OEM STIHL (p/n#0000 400 1300) universal unlimited coil with 2 poles and it works. I then advanced the timing via the flywheel key by removing ~.020" and now the tach doesn't go haywire, since there is no limiter to bounce off of and she's tuned much better.
Good choice. I got a OEM 0000 400 1300 module on my '92 066 Mag and still going strong after 26 years.
Quote from: gowanus2015 on March 28, 2018, 12:48:58 PM
UPDATE:
As Joe_Indi suggested I ended up getting a cheap used OEM STIHL (p/n#0000 400 1300) coil with 2 poles and it works. I then advanced the timing via the flywheel key by removing ~.020" and now the tach doesn't go haywire, since there is no limiter to bounce off of and she's tuned much better.
Is that coil plug/play?
yes, plug and play if it comes with the plug wire. if not you can always transfer your current plug wire. FYI: it only has 2 poles and 2 screw the original 461 limited coil had 3 poles and 3 screws. it holds fine with only 2 screws, you just have one open hole. no big deal. make sure to gap the coil according to the manual. revvvvvvvvv and go!