How To Fix The MS661 Bog

[Canadian farm boy]

We do. Just gotta look harder

 

[Duane(Pa)]

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

50:1? That is what oil is supposed to prevent.... Maybe the EPA doesn't care about piston skirts?

 

[Mastermind]

I got quite a shock when I tore into this well used MS661 that belongs to The Cobby.

It had plenty of oil in the bottom end, and was pretty damn clean.

It has been run on Stihl Ultra @ 50:1 it's whole life.

 

[Redfin]

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.

In my feable mind reading through all that thread I was thinking the same. That's why I asked about elevation and all that responded were at low alts. Thanks for putting this up Randy.

 

[Mastermind]

When I read that thread........I laughed my ass off.

 

[Cobby08]

As did most


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[bryanr2]

ha ha. found it.

 

[bryanr2]

As did most


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that's why we read it. didn't expect to learn from it.

 

[thomas1]

How many different gas caps did you try before you found out the coil was the problem?

 

[Mastermind]

EleventyOne

 

[Glock37]

Whats the stihl part number for the new coil and upgraded intake boot


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[Mastermind]

Whats the stihl part number for the new coil and upgraded intake boot


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The new control module is 1144-400-4720

@Cobby08 what is the # for the new intake?

 

[spencerpaving]

I like to put a small 20* bevel on the intake side of pistons on the skirt....instead of the sharp edge scraping the oil off the side of the cyl the bevel seems to hold it in better....also I think it helps with the incoming rush of air and fuel into the case....plus if you bevel it to half the thickness of the piston it doesn't change intake timing.....jmo

 

[Mastermind]

That is a damn good idea Bret.

Filing that away for later my friend.

 

[Cobby08]

1144 141 2202


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[Mastermind]

Thank you Mark.

 

[Cobby08]

Yessir. If you remind me I'll try to figure how to hook up the old module too to check fuel rates and hours.


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[Mastermind]

But I just chiseled it apart. I heard those details were in there......and I wanted to see em.

 

[Cobby08]

I should of thought of that!


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[Mastermind]

Yeah.....well you ain't smart like me.