I'm a Husqvarma guy. I have NOTHING against Stihl. They are great saws. I recently bought a 372XP with a 20" bar and absolutely love it. Going from my old 359 was a night and day difference. Friday evening I found a deal on a 660 with a 20" bar (who does that?). So I pursued it and bought it Saturday night. The guy i bought it from is a clear cutter, a foreman, so the saw is a year old and has seen some work and some tool box time and the plastic reflects that. It's start and runs great. Sunday I was very anxious to see the beast sink into some wood. My brother and i were falling standing dead oaks. I grabbed the Sthil and approached a 15-18" white oak. Started to cut the notch and noticed the saw would bog slightly, about like my 372 would if I pushed too hard. I was shocked. I dropped the tree and made a couple of cuts, long enough to pull with the tractor. All that to say that I was disappointed. I figure jumping up 24cc would be an incredible difference. What could be wrong? I texted the previous owner this evening and he recommended changing the fuel filter, and I will. While running the saw, there was no indication of anything wrong. Where should I start?
Bogging can be from several different things. Your chain was to aggressive, you have an ill adjusted carb, clutch/brake band problems, or a couple other likely issues. Do you have a YouTube account? A video is the best option to see and hear different problems.
I failed to mention it has a brand new Stihl bar and Oregon blue link chain, 72LGX. I do have a YouTube account. I'll see if I can't get something up Wednesday.
The 660 is a known underperformer in stock trim. If the saw seems down on power but running correctly, a muffler mod (or dual-port conversion) may help but I doubt it's going to make the night and day difference you're looking for. I would grab a loop of chain you know performs well and try it on the 660 before you condemn it to "turd" status however. They can be made to run very strong but the level of work involved generally exceeds DIY capabilities.
pull the muffler cover. That saw should not bog with a 20" bar unless there are issues, it could be carb related as it is cold out, but that is a common logging setup around here (066 20" bar for the amish) so they can PRY on it with a dull chain to cut.
Hey Josh, clarify something for us.... Does the saw bog like it's starving for fuel or (as I suspect) were you just expecting a big power increase from your 372? Even tho the 660 doesn't exactly set the woods on fire, it shouldn't have power problems in 15-18" wood. However, even a perfect running example probably wouldn't be any faster in 15-18" wood than your 372.
Also watch the air filter. The first series air filters on the MS660 Magnums lets WAY more dust through than i wanted. Was REALLY shocked after cutting with it on the first day I had mine. This is the first series/bad filter with prefilter lifted off. This is the new upgrade filter. I had to order mine online as our local Stihl parts distributer wouldn't sell the upgraded ones till all the old ones were gone. Dealer said they couldn't get them. VERY bad business to me. This was a couple years ago. Bad thing is I went to the dealer to order some part 2 weeks ago and they had a new MS660 there. pulled the air cleaner cover off and guess what? First series air filter.
I agree it may be a carb issue, but a clogged air filter could cause this as well, less air will cause all kinds of problems. I cast my vote for a carburetor adjustment/replacement though, or a mix of the two since it's been used heavily.
Thanks for replies. We did pull the air filter cover off when we met to buy it. It looked good, it was a white paper filter that appeared to be pretty new based on a quick glance, but I'll certainly pull it off. The drive sprocket-I do not know at this time. I'm still running the stock chain on my 372, only about 4 tanks in on it. It's the H48x-72 chain loop. I've used the Oregon 72LGX chains for year, and quite honestly a 96cc saw (running right) ought not bog with what ever chain in a small dead white oak. I was looking for that extra power compared to my 372, as I said I saw going from the 359 to the 372. As far as the bog, it would bog, not like I had to stop because it wouldn't run the chain, but loose some RPMs when I'd pull up on the handle to dig the dawgs into the tree. That make sense? All the mods will certainly make it run better, will make any saw run better, but in stock form this thing should be amazing. Maybe it needs a set of rings? I'm going to see if I can get my hands on a compression tester. I'll probably pick up a fuel filter, spark plug and air filter today.
Whoops, but still at 20cc bigger than my 372 it ought to impress me. I'll try to all the suggestions this evening. Thank you all.
