Problematic MS661

[Andyshine77]

Sounds like you figured it out. I find it hard to believe Stihl didn't account for the cfm requirements. What happens when the filter gets dirty?

Brad's 661 was really strong, and didn't miss a beat with the 32" bar buried in an ash stump, but it did have that off idle bog from time to time. Hopefully this will fix the problem.

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[blsnelling]

Sounds like you figured it out. I find it hard to believe Stihl account for the cfm requirements. What happens when the filter gets dirty?

Brad's 661 was really strong, and didn't miss a beat with the 32" bar buried in an ash stump, but it did have that off idle bog from time to time. Hopefully this will fix the problem.

Sent from my HTC One_M8 using Tapatalk

36"

 

[Moparmyway]

Sounds like you figured it out. I find it hard to believe Stihl account for the cfm requirements. What happens when the filter gets dirty?

Brad's 661 was really strong, and didn't miss a beat with the 32" bar buried in an ash stump, but it did have that off idle bog from time to time. Hopefully this will fix the problem.

Lets look at it this way ...........
- The carb is "supposed" to compensate for restricted air filters .......... but a hopped up 91cc saw takes in more air than a stock 91cc saw
- Stihl redesigned the intake boot and offers one that is stiffer and without any bellows.
- 91cc is a HUGE draw, and the same HD2 filter is used on saws 1/2 its displacement (I believe the HD2 on the 661 is Stihls biggest mistake)
- IIRC, Brads has the newly designed straight intake ........... ?????


I really want to see how Brads responds to the Max Flow - and am waiting on the edge of my seat to hear from him on it.

 

[blsnelling]

Stop it! I'm getting really anxious to try this filter. I was sceptical at first, but it's hard to deny practical experience. Like I told someone the other day, without evidence it's just an opinion. You've provided the evidence. I'm cautiously optimistic

 

[mdavlee]

Stihl filters suck. I gave away the HD 2 I had. I don't run a single stihl filter on the 044 and 046s.

 

[blsnelling]

On another note, I can't really knock Stihl or MTronic design if this fixes it. I'm way outside the design parameters of this saw. This saw will hold 12,500+ with a 36" bar buried. It's happiest around 11,000-11,500. That's some real RPMs for a 90cc class saw. It'll just be an integral part of the mod.

 

[Moparmyway]

Stop it! I'm getting really anxious to try this filter. I was sceptical at first, but it's hard to deny practical experience. Like I told someone the other day, without evidence it's just an opinion. You've provided the evidence. I'm cautiously optimistic

I only provided the ramblings of an anal engineer on his own modified POS 91cc creamsickle, and suggested you consider the theory behind a better flowing air filter

I am hoping you have the same results because then I wouldnt feel like an azz

 

[Moparmyway]

Stihl filters suck.

I gave away the HD 2 I had. I don't run a single stihl filter on the 044 and 046s.

QTLA !!

About the only thing I use the stock Stihl filter for is the frame. Makes for purchasing the Max Flow element only and saves me cabbage. In this light, I preferr the HD filter, so if anyone has any extra ones laying around, I'd be willing to grab them from ya !!!

 

[Andyshine77]

Very interested to see how this goes. All in all it makes total sense, and is potentially an easy fix for Stihl, as I believe some stock saws have this issue as well??

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[Moparmyway]

If the Max Flow dont fix Brads, I'd be willing to purchase the kit from him, and re-imburse for shipping if he dont want it ................. I could use it

 

[Andyshine77]

On another note, I can't really knock Stihl or MTronic design if this fixes it. I'm way outside the design parameters of this saw. This saw will hold 12,500+ with a 36" bar buried. It's happiest around 11,000-11,500. That's some real RPMs for a 90cc class saw. It'll just be an integral part of the mod.

Agreed. But again if the filter becomes restricted when dirty what happens? As a dirty filter would essentially cause the same problem on a stock saw. Just thinking out loud here.

 

[blsnelling]

If the Max Flow dont fix Brads, I'd be willing to purchase the kit from him, and re-imburse for shipping if he dont want it ................. I could use it

I can't lose

 

[Moparmyway]

Agreed. But again if the filter becomes restricted when dirty what happens? As a dirty filter would essentially cause the same problem on a stock saw. Just thinking out loud here.

Think muffler opening on a stock 661

 

[Stihlman441]

Try running it without the filter,put a stocking or something over the carb throat.

 

[blsnelling]

I think I mentioned it earlier, but this only showed up after I removed the baffle in the muffler and further opened it up. I have another muffler to throw on to test that, but am unwilling to leave it that way. It improved performance. We just have to find a way to work around it.

 

[Moparmyway]

I can't lose

No Sir ............ you cant !
You wont be out a single cent if you dont see a difference

 

[Moparmyway]

Try running it without the filter,put a stocking or something over the carb throat.

I would wait for the filter, just to ensure fines dont pass through

 

[Andyshine77]

Think muffler opening on a stock 661

There you go.[emoji106]

 

[Moparmyway]

I think I mentioned it earlier, but this only showed up after I removed the baffle in the muffler and further opened it up. I have another muffler to throw on to test that, but am unwilling to leave it that way. It improved performance. We just have to find a way to work around it.

I am going to order a new muffler for my 661 after the new year so I can play around

 

[chris zautner]

http://s404.photobucket.com/user/cobby08/media/C74A8312-46FF-421D-8816-784E4F6B76F7.mp4.html
This was better then it was but still annoying.

my saw is just like that