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MS310 muffler mod/carb tune...

Started by mrcaptainbob, May 09, 2009, 10:01:06 PM

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mrcaptainbob

I plan to do some of the muffler mods to my four year old MS310 as suggested here. My son suggested upping the jet size a bit, too. I remember reading something about adjusting the carb to compensate the muffler mod, but can't remember what it was....
The plan for the muffler is two 3/8" holes. The carb mod=?

Thanks for the help....


mrcaptainbob

Thanks, Rocky_J. I was told also that the carb might need a different metering valve. I see by these directions that may not be necessary.

GASoline71

Just need to prolly richen the H screw is all... no need to pull the carb.  Just retune.  I personally don't understand why someone would wanna do any kind mod on a 310 firewood saw... but that's just me.

Remember... if not retuned properly... you run a chance to run the saw lean...

lean = bad ju-ju.

Gary
\"...if ya mess with the bull... ya gets the horn.\"

mrcaptainbob

It sounds like you're not in favor of  a muffler mod on this saw, GASoline71. Why is that? Not a big enough saw to make a diff? I don't want to do something that won't work or otherwise muck up an otherwise good running saw. Thanks for any guidance....

GASoline71

A little about my theories about "modding" saws... I am a fan of saws in their stock form.  Any "mods" will be like a factory Dual-port muffler cover like Stihl offers for the 046/460 and the 066/660.  Those types of saws really benefit from a "mod".  They are large cc pro saws that are built to take the punishment that loggers dish out.  There are a handful of saw shops here in the PNW that still do professional mods to the cylinders for pro users.  Harry Homeowner will usually be turned away if they inquire about a cylinder mod...

The typical homeowner saw... 290/310/390... does not need anything for the casual user.  If a mod is "needed" to pull a bigger bar and chain combo... usually you need to step up to a bigger saw for the job.  So my basic point is... if it ain't broke, don't "fix" it.  Saws under 60cc's are worthless to mod.  But again... this is only my opinion.  There are a lot of guys that will still do it... and like the results.  I personally think modding small saws is a waste of time.  Again... that's me.

On the other end of the spectrum is a guy like Brian (Rocky_J)... he uses professionally modified pro saws exclusively.  He is a professional arborist, and needs every ounce of power out of his saws.  He loves them.  The advantage being, using a lighter saw... that will do the work of a larger, heavier saw.  His pro modified 372XP will prolly do the work of a 385XP or a 390XP at a third of the weight up in the tree.

There are big benefits to a mod... but small saws are a waste of time.

If you are just playin' around and learnin' and don't mind the possiblity of makin' a mistake that can fry a $300 dollar piece of equipment... go for it.  :)  Just remember that small mistakes in modding saws can be costly.  It ain't rocket science to do a muffler mod... but if the saw is not retuned properly you can lean it out and score the P&C.

Okay... there... that, in a nutshell, is how I think about saw mods... :)

Gary
\"...if ya mess with the bull... ya gets the horn.\"

John Mc

Gary - your arguments make a lot of sense. For the most part, for a typical homeowner/landowner type user, if a stock saw won't cut it, you probably just need a larger saw. I can think of a couple of exceptions:

1) the catalytic mufflers I've had experience with are very restrictive. My Jonsered 2152-C ran way too hot with the stock catalytic muffler. I swapped it out and it ran much cooler and more reliably. The extra power was also a nice bonus. It was definitely worth the swap. That was before I knew how to tune a saw, so I brought it into the local shop for a tune after the muffler swap.

2) It's not just pro users who might consider the weight savings a bonus. I've got some nagging upper back and neck injuries which are aggravated by using a chainsaw (if I use one for more than a couple hours at a stretch). I imagine some of those who are getting up there in years might similarly appreciate a lighter saw as well. I'm not talking about a full-blown woods port, but a simple muffler mod might be worth it, if it avoids having to trade up for a larger saw.
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

Rocky_J

Gary, I like you and respect you but in this case I'm going to disagree. We're only talking muffler mods here, not woods porting. Think of it like putting dual exhaust on your stock 6 cylinder pickup truck versus rebuilding the motor with a 3/4 cam. Opening up the exhaust and dialing the carb in are pretty basic and practically every saw made and sold in the USA in the last 20 years can benefit a little (except the saws with fixed jet carbs/ no adjustment capabilities).

Here's the carb tuning info page again. :)
http://www.madsens1.com/saw%20carb%20tune.htm

mrcaptainbob

Your points make sense, GASoline71. Will take that into consideration as well as the counter points. I was thinking that some simple/easy changes would improve the existing perfomance would be a benefit to both, the saw and me. I don't expect it to become as powerful as the next size up, just any thing to improve what's there. Thanks, all for the advice and counsel...

nmurph

well, i respect gary, but i disagree. a MM does wonders for this saw. why spend the money for a new saw when 10 minutes with a drill will get you the same effect. i will try to get some pics up tomorrow of mine.

GASoline71

You know what... I was completely thinking big time woods porting and stuff when I typed all that... I guess it helps if you go back and reread the original question... oops :-\ ;) :D

I agree with you'se guys about the muffler mods... I did say that they aren't rocket science, and are pretty straight forward.  Let 'er rip.  :)

Gary
\"...if ya mess with the bull... ya gets the horn.\"

Al_Smith

 You can gain some power by widdening the ex port a tad bit and belling out the port but you won't turn it into a screamer .

That said a simple reworking of the muffler is about all that can be done to saw engines of this design .

timber tramp

  Since we're on the subject, does anyone have any first hand experience with the dual port muffler for an 044 from Baileys?? Part #QA 11281 400616. Worth the $50, or just louder?         
             Thanks,  :) TT
Cause every good story needs a villan!

GASoline71

A dual port is actually an 046/460 muffler cover.  They happen to share the same muffler base as an 044/440... They do work well on the 046/460's I have ran... I know people that do it... but I have never used one on an 044/440.

All you really need is the cover (unless you're missing the entire muffler)... I can get the cover from my local Stohl dealer for about $25 - $30 bucks.

Stihl part number 1128 145 0805

Gary
\"...if ya mess with the bull... ya gets the horn.\"

Al_Smith

 All it is is another hole with a shroud .

You want a fast muffler ,just gut everything out of it,no baffles at all .Stick another hole out the side.If you want the screens ,leave them in ,no big deal .

As has been said 40 zillion times retune the carb then make sure you wear good hearing protection because it will be loud but then it will be much faster  as  a result .

It's so simple anyone with one ounce of mechanical ability and a few tools can do .It's so easy I can even have success .

A two cycle engine works on differential pressures .It takes fuel to make power.Fuel can't get in if the exhaust can't get out .

timber tramp

  Gary and Al - thanks for the answers, I think I'll leave my muffler alone. ;)     :) TT
Cause every good story needs a villan!

scottedward58

do the mod. I did it to my MS290 before I turned it in to a MS390, by bolting on a 390 piston and cylinder and it really woke it up. by the way if you didn't know the MS290-310-390 are all the same just diferent bore same stroke so all the cylinders interchange which is a great way to gain more power if you ever need to replace a p&c. I did some minor port work and between that the muffler mod, a 044 carb & the 390 jug I can now pull a full comp chain on a 28" bar no problem.

nmurph

i really don't understand why someone would not do the MM on this saw. it is SOOOOO simple and gives a significant power boost.

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