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MS 461 "De-Limiting" the Speed Limiter

Started by joe_indi, January 01, 2014, 06:31:38 AM

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John Mc

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.
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

joe_indi

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




joe_indi

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.

4x4American

Boy, back in my day..

Wildman Ben

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?

joe_indi

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

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.

ladylake


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
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

John Mc

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?
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

Wildman Ben

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.

John Mc

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.
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

ZeroJunk

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.

Wildman Ben

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?

joe_indi

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.

JohnG28

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
  ;)
Stihl MS361, 460 & 200T, Jonsered 490, Jonsereds 90, Husky 350 & 142, Homelite XL and Super XL

gowanus2015

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?

ladylake

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
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

HolmenTree

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.
Making a living with a saw since age 16.

joe_indi

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.

gowanus2015

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!

gowanus2015

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.  

HolmenTree

Good choice. I got a OEM 0000 400 1300 module on my '92 066 Mag and still going strong after 26 years.
Making a living with a saw since age 16.

4x4American

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?
Boy, back in my day..

gowanus2015

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!

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