ms 660 problem

[canoehead]

milling for about four hours, then something gone, clutch? haven't stripped it apart yet, engine runs fine; chain rotates, only without power. any ideas?? oldish saw (5-6 years) have used very heavily this year, its cut and milled a house worth of timber. can't complain. just want to fix it asap as have more milling to attend to.

 

here's a pic of my timber frame under construction.

[antipesto]

I would probably say the clutch is knackered or maybe the drive sprocket has rounded off etc. Strip it and see, should be a cheap fix and well worth it on a 660:thumbup1:

[agg221]

I would agree with above - both have gone at various points with my 066 which is mainly used for milling.

 

If you do have to replace the sprocket and currently have a rim sprocket it's worth replacing with a spur one for milling - they last better apparently under constant load conditions.

 

Alec

[Rob D]

Does the chain rotate when you pull it over to start it? If so is most likely the needle bearing the sprocket sits on.

 

An easy fix.

[Megatron]

Does the chain rotate when you pull it over to start it? If so is most likely the needle bearing the sprocket sits on.

 

An easy fix.

 

This wouldn't explain the lack of drive of the chain. The needle bearing is only in operation when at idle or with chain break on.

[spudulike]

Need a bit more info to make an educated guess - if the saw is cutting and under load the revs soar and the chain speed slows then it is the clutch, if the saw just bogs and lacks power then it sounds like low compression or fuel/air problem.

 

I can't imagine the chain is spinning round the sprocket and a bad sprocket bearing wouldnt loose you much power as the sprocket is locked against the clutch during a cut.

 

I would pull the muffler and inspect the piston - you may have part seized it:thumbdown: Measuring the compression would be good but the inspection will give you the info you need. I would make sure the air filter is clean and worth looking at the colour of the plug - if you get stuck then am happy to take a look - had AGG221s 066 magnum apart and sorted - a keen miller as well and I am not talking flour:thumbup:

[agg221]

I can't imagine the chain is spinning round the sprocket

 

It can - I had it with a rim sprocket once where the chain jumped the sockets. It happens more easily with long bars and milling as the long cuts warm the chain up and the total 'give' is greater.

 

With a spur sprocket it tends to drop into the low-spot at which point the chain goes slack - tension it again and it will stay in place, but it's a sign that it's time to change it!

 

Alec

[spudulike]

That can't sound too nice and must vibrate a bit!

[canoehead]

thanks everyone for your replies. really appreciate it. i stopped using it yesterday when it cut out driving the chain. started it a couple of times. the engine ran fine, and drove the chain forward a bit, but without power. will be stripping it down this weekend for an examination, and report back. thanks again.

[canoehead]

it is the sprocket/clutch drum they've parted company.