MS660 running rough

[Billy Goat Gruff]

My 660 has been playing up so last year (Nov) went to use it and there was no power in it. when I started cutting the revs died.

So took it to a local dealer, who said the piston was scored on the exhaust port side. It was I saw the piston afterwards. A new piston and rings were fitted, he said the barrel was O.K. I used it a few times with the 25" bar on some conifers and it was o.k. but last week took down a large Oak 15' girth

I felled it o.k with the saw, but when it came to ringing up the sections again it just lost power as before. I was using the 36" bar on it. I know that this is the biggest bar that can be used on the 660, was it just a case of using the biggest bar and cutting through large sections of hardwood Oak, with lots of sawdust clogging every thing or should it have performed with ease??

It had a brand new chain on that morning.

Your experiences and comments would be appreciated, as if I take it to the local dealer again, I will be at his mercy and the bill last time was not cheap!!

[Mesterh]

I dont think it will be the bar size or the dust etc. We run a 66 with a 36" bar all day long and it hasnt had any probs with scoring the piston etc.

Looks like you may have other problems like air leaks or cooling probs since it didnt last very long after the new piston.

[ukminch]

I'd agree it sounds like there's something else amiss. Have you tried the saw since, and did it start up ok, wondering like mesterh if whatever else is wrong has goosed another piston.

 

Rob

[Ironbark]

What caused the scoring in the first place? Maybe running lean due air leak or carb adjustment.

 

Hope it hasn't happened again.

[Husqvarna King]

hey mate, i have also had trouble with my 660, different problem to you but took it to Stanton Hope - Essex and they were a great help. give them a try

[MarshallArb]

i had similar problem with a 441 it had a hole in fuel line causing it to run lean but it could also be as simple as an faulty batch of 2 stroke or using inferior brand oil. you can check if its running lean cos the plug will be white.

[Billy Goat Gruff]

Thanks Guys,

My worst fears confirmed, will have to be another trip to the dealers and another spend out, but I hate things not working properly, so will sort it out. I will probably take it to Stantons, like you have suggested, (thanks Husqvarna King)

I think the problem was that it was running lean for some reason, due to the scoring on the exhaust port side.