MS361 Muffler Mod Attempt #1

[5shot]

I bought this saw back in 2007 for firewood cutting, but a couple years later we moved cities and away went our wood stove. It has not seen much use at all, and I finally decided I should mod the muffler and get it out on my dad's property to put it to use.

I liked the Lakeside mod, but don't have any welding equipment, so I ended up getting the Husky Diverter and spark screen. I did a quick calculation on the area of the holes in the baffle, and like Lake had said before, they aren't the problem, the tiny exit hole is. I used an awl to transfer the entire area of the diverter opening onto the side of the muffler and then drilled and dremeled the port out. It ran good, but the screen choked off half the air flow. We have fires all over the place, so running without a screen is a no go. I decided I need more screen area to achieve what he had done, so I set about making a pattern for a screen that had enough flow. This one ends up with at least 3x the flow of the flat screen and probably closer to 4. That gives more than 150% of the flow required to utilize the entire port area (which is the same size as the muffler gasket opening. I would guess it is much larger than the area of the exhaust port at the cylinder. I ordered some 30Mesh from Amazon and it worked damn good for the first try. It is a tad tight, since the thickness of the screen is a bit more than the manila folder, but it doesn't really need to come back out. You can burn off the junk by removing the diverter only. Saw idles great and runs really well. I tuned it back to just under 14K at WOT, but I'll burry it in some wood and retune to see what it can do.

 

[Wood Doctor]

I have never modded the muffler on my MS361 that I bought about 13 years ago. I may have to reconsider that decision after seeing how nicely you did it here. It has always been a good saw, perhaps the best all-new saw that I ever bought. Great job, 5shot!

 

[bwalker]

I remember like side saying the internal baffle didn't cause any restriction. I have not tested it so I can't say for certain, but I feel it not only does screw up flow, it also holds in heat.

 

[5shot]

I remember like side saying the internal baffle didn't cause any restriction. I have not tested it so I can't say for certain, but I feel it not only does screw up flow, it also holds in heat.

I don't doubt that. At some point I may find a cheap one off ebay and tear into it, but for now it isn't a priority. The rest of the saw is stock and more than enough for Eastern WA pines and firs.

 

[Canyon Angler]

Pretty sure I followed Lakeside's instructions to mod my 361 muffler. IIRC he said to drill some holes in the internal baffle, and I think that's what I did (you need to be sure to get all the steel swarf out, I think I used some kerosene and compressed air to wash/blow it all out before brazing it shut).

 

[LogSawyer74]

When I do a 361 muffler, I use a paint can opener tool to uncrimp it. Still a huge pain, but once I get it apart, I just cut out all the junk on the inside and open up the outlet hole. I crimp it all back together with a small hammer and vice grips, and you can never tell it's been opened up. Makes it quite a bit louder tho.

 

[bwalker]

I don't doubt that. At some point I may find a cheap one off ebay and tear into it, but for now it isn't a priority. The rest of the saw is stock and more than enough for Eastern WA pines and firs.

Might look at a 362 two piece muffler. I have one for my 361 right now. I just need to fab up a bracket for the third screw.

 

[5shot]

Might look at a 362 two piece muffler. I have one for my 361 right now. I just need to fab up a bracket for the third screw.

I did think about that. Kind of pricey, so I'll see how this works out before spending the coin on the 2 piece. I'm not going to be using this saw day in and day out.

 

[Roy Cobb]

I did the exact mod to mine easy to do. Used the Husky deflector and screen runs good.

 

[LogSawyer74]

I bought this saw back in 2007 for firewood cutting, but a couple years later we moved cities and away went our wood stove. It has not seen much use at all, and I finally decided I should mod the muffler and get it out on my dad's property to put it to use.

I liked the Lakeside mod, but don't have any welding equipment, so I ended up getting the Husky Diverter and spark screen. I did a quick calculation on the area of the holes in the baffle, and like Lake had said before, they aren't the problem, the tiny exit hole is. I used an awl to transfer the entire area of the diverter opening onto the side of the muffler and then drilled and dremeled the port out. It ran good, but the screen choked off half the air flow. We have fires all over the place, so running without a screen is a no go. I decided I need more screen area to achieve what he had done, so I set about making a pattern for a screen that had enough flow. This one ends up with at least 3x the flow of the flat screen and probably closer to 4. That gives more than 150% of the flow required to utilize the entire port area (which is the same size as the muffler gasket opening. I would guess it is much larger than the area of the exhaust port at the cylinder. I ordered some 30Mesh from Amazon and it worked damn good for the first try. It is a tad tight, since the thickness of the screen is a bit more than the manila folder, but it doesn't really need to come back out. You can burn off the junk by removing the diverter only. Saw idles great and runs really well. I tuned it back to just under 14K at WOT, but I'll burry it in some wood and retune to see what it can do.

Do you have the Husky part # for the deflector on hand? thanks

 

[cuinrearview]

I don't see any way that all of this garbage doesn't restrict flow. Punching extra holes will certainly help but I'm a big fan of empty cans.

 

[5shot]

Do you have the Husky part # for the deflector on hand? thanks

Husqvarna 503078301 Exhaust Outlet

 

[5shot]

I don't see any way that all of this garbage doesn't restrict flow. Punching extra holes will certainly help but I'm a big fan of empty cans.

I'm sure it does, but you definitely gain even without tearing it apart.

 

[bwalker]

I don't see any way that all of this garbage doesn't restrict flow. Punching extra holes will certainly help but I'm a big fan of empty cans.

Yep.

 

[Mad Professor]

Anybody been in contact with Lakeside/Andy?

 

[cuinrearview]

Husqvarna 503078301 Exhaust Outlet

@Red97 can get you some sweet deflectors. He could probably even make them screw/rivet on like those for you.

 

[ballisticdoughnut]

I bought this saw back in 2007 for firewood cutting, but a couple years later we moved cities and away went our wood stove. It has not seen much use at all, and I finally decided I should mod the muffler and get it out on my dad's property to put it to use.

I liked the Lakeside mod, but don't have any welding equipment, so I ended up getting the Husky Diverter and spark screen. I did a quick calculation on the area of the holes in the baffle, and like Lake had said before, they aren't the problem, the tiny exit hole is. I used an awl to transfer the entire area of the diverter opening onto the side of the muffler and then drilled and dremeled the port out. It ran good, but the screen choked off half the air flow. We have fires all over the place, so running without a screen is a no go. I decided I need more screen area to achieve what he had done, so I set about making a pattern for a screen that had enough flow. This one ends up with at least 3x the flow of the flat screen and probably closer to 4. That gives more than 150% of the flow required to utilize the entire port area (which is the same size as the muffler gasket opening. I would guess it is much larger than the area of the exhaust port at the cylinder. I ordered some 30Mesh from Amazon and it worked damn good for the first try. It is a tad tight, since the thickness of the screen is a bit more than the manila folder, but it doesn't really need to come back out. You can burn off the junk by removing the diverter only. Saw idles great and runs really well. I tuned it back to just under 14K at WOT, but I'll burry it in some wood and retune to see what it can do.

I know this is kinda old but I must say i really like how you've done this muffler mod. Building the spark screen the way you did is a great idea. Maximum surface area. I will be doing the same from now on. Excellent work.

 

[Evan]

I always felt a single outlet is best.
Exhaust pulses and Sound waves change when adding ports.

I to would gut the junk out of that muffler.

Does look like a very well done muffler

 

[ballisticdoughnut]

I always felt a single outlet is best.
Exhaust pulses and Sound waves change when adding ports.

I to would gut the junk out of that muffler.

Does look like a very well done muffler

I agree, a single properly sized outlet is what I would prefer. I will say however, both my 038 mags have factory triple port mufflers.

 

[bwalker]

I am fooling around with a 2 piece Ms362 muffler on my 361 right now. To get this to work you need a 034 exhaust spacer and two nuts tack welded on to the back of the muffler. Exhaust discharge clearance at the chain brake is tight, but I think it will work. If it does I will have a bracket welded on to the front cover in order to use the stock 361 front muffler mount.