Older MS661c Fuel Solenoid Issue?

[arborlicious]

My five year old MS661c has been giving me grief lately. It won't hold idle for long before it cuts out and then I always have to put it in the cold start position ▲ to get it going again, i.e. no warm start in the "I" position.

 

Have gone through the usual suspects, new spark plug, clean air filter (actually replaced with a brand spanking HD2). Compression is still spot on at 165psi.

 

Have performed the M-tronic reset (90 seconds in start position ▲ then stop.) During the re-calibration the saw seems to stay at the same RPM–is that normal?

 

I've heard that these older MS661c had problems with the fuel solenoids and control units so I'm thinking to do an upgrade. There is a specific MS661c service kit (1144 007 1801) containing a new solenoid, fuel filter and v3 control unit (1144 400 4703 or 1144 400 4704)

 

I suppose I should take it to the local dealer and they can run the diagnostic checks but I don't want to pay them $60 then to tell me I need a $30 solenoid...

 

 

[spudulike]

Just fit a new one and if it isn't that, you have only done £20! The issue was the first ones got very fine chip in them so they bought out a new one and it comes with a much finer fuel filter so change that as well!

[arborlicious]

Ordered the MS661c service kit yesterday so I'll report back with the results.

[spudulike]

Best way, fit it and see what it does, if it doesn't work, hand it over to someone who can take it to the next stage.

[arborlicious]

While I'm waiting, decided to take off the cylinder and see how it looks after 5 years.

 

Still looking good–obviously I don't use this saw every day. Always use full synthetic 2 stroke at 50:1.

 

 

[Echo]

Are the rings free in the groove, you also have vertical scoring in the cylinder.

What kind of oil do you use, is it Stihl Ultra.

I would clean up that piston, and put new rings and base gasket on there now you have it opened.

Edited October 30, 2020 by Echo

[Paddy1000111]

14 hours ago, Echo said:

Are the rings free in the groove, you also have vertical scoring in the cylinder.

What kind of oil do you use, is it Stihl Ultra.

I would clean up that piston, and put new rings and base gasket on there now you have it opened.

A few people have mentioned Stihl Ultra. Without hi-jacking this thread into a OPE forum oil debate, are people having issues with it?

[Echo]

@Paddy1000111,I have heard of no issues, some say it does not burn so clean

I used Husqvarna XP fully synthetic, anything I opened up was as

clean as I like things, I have not used the Stihl oil, am currently using

Mobil1 2T, not sure about it yet, no problems, but in the same saw there 

seems to be less oil deposits on the piston sides, no heating or indication

of any issues, just makes me curious, I think its a more full bodied oil with

higher flash point, probably be better in a larger saw, I was very surprised by 

the Echo X Blend semi oil, real nice deposits and very clean insides.

 

[Echo]

I think this guy shows a piston after running Stihl Ultra

 

 

Edited October 31, 2020 by Echo

[Stubby]

7 hours ago, Paddy1000111 said:

A few people have mentioned Stihl Ultra. Without hi-jacking this thread into a OPE forum oil debate, are people having issues with it?

Not me as I use Red Line Racing . ?