How To Fix The MS661 Bog

[Mastermind]

I remember a big screwed up thread over on AS about a guy that had a MS661 that was bogging.

Here's the fix.......

Old coil.



Take that off and install this new coil.


Yes.......it's that simple.

If you have a decent dealer it won't cost you a penny.......

 

[Canadian farm boy]

So this is an update from stihl for the 661 like the intake tube?

 

[Mastermind]

So this is an update from stihl for the 661 like the intake tube?

Yes sir. That is exactly what it is. This new coil "control module" fattens the saw up a bunch. The bog was caused by it being too lean on the low side.....

The strange thing is that not all the "old" modules were acting this way.

 

[Cobby08]

Well would you look at that...


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[Mastermind]

Here's something I see on every 661 I tear down.......even in the brand new ones.

 

[Cobby08]

Wow that's a good feeling to have lol


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[Gunn]

Randy which intake is better (solid vs bellowed)? What's the consensus about the washers?

 

[Rains]

I knew you were sitting back with a grin !!!

 

[cgraham1]

Here's something I see on every 661 I tear down.......even in the brand new ones.

View attachment 6321

What the *f-word?!! How does that happen?

 

[CR888]

That thread was like a train wreck that smashed derailed then jumped back onto the tracks and continued into a head on with another train with no survivors. It was a frustrating read that left more questions than answers. Glad you have given a simple clear answer/solution to the issue.

 

[petedaycab]

I remember a big screwed up thread over on AS about a guy that had a MS661 that was bogging.

Here's the fix.......

Old coil.

View attachment 6313

Take that off and install this new coil.

View attachment 6314
Yes.......it's that simple.

If you have a decent dealer it won't cost you a penny.......

Well, that seems simple enough.

 

[Mastermind]

Randy which intake is better (solid vs bellowed)? What's the consensus about the washers?

Use the solid intake. The washers were used to give the bellowed intake more strength.

 

[CR888]

Use the solid intake. The washers were used to give the bellowed intake more strength.

Once removed, the intake would collapse under vacuum. A crude solution from stihl to a problem dicovered post production, but like they do always they updated the part and solved the issue. I don't have a 661 & was not in any rush to be the first as I have a good MM660, despite everyone believing the new 661 was going to be the holy grail saw & save the earth from everything all new ope models have little design faults that get fixed down the road. What is good about stihl is they constantly evolve and update their products.

 

[jacob j.]

What the *f-word?!! How does that happen?

It looks like the piston rocks a little before the engine warms up.

 

[Mastermind]

I agree JJ. The reason I think that is where this wear comes from, is because I see it in new saws.

 

[so il logger]

I just pulled the starter off of mine, it has the 4700 C module. The saw performs / runs great. Should i try to get the dealer to replace the module? Or should it be fine as is?

 

[Cobby08]

Mine did as well


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[Mastermind]

If it is running well.......I wouldn't worry.

Here's what I've noticed on the ones that need more fuel. You will come off of a big cut and the saw will hurt around for idle and sound "off"......

 

[bryanr2]

why the hell do we not have a popcorn emoji?

 

[Canadian farm boy]

why the hell do we not have a popcorn emoji?