# Chain saw cat muffler.



## alleyyooper (Apr 22, 2005)

Finally desided to do some thing with the muffler on my Jonsered 2159T chain saw you hve to wear an ove glove to run. This how hot it runs and about 5 years of use.










I was just going to cut in half and remove some of the blockage and cut an new exit for the ehaust and weld the old exit up.

The ragged whole is where I drilled into the blockage to see if that much helped. 



















the pipes inside routed the exhaust that made it to the front of the saw back to the rear and top to exit.



















Decided modifing the muffler just didn't work like I wanted, Pitched the scrap in the scrap pile and bought a aftermarket Non cat muffler. installed it and removed the limiters and gave the hi jet a 1/4 turn open. Now I can run the saw with bare hands and not roast them. The saw cuts much faster thru a 18 inch Ash round by about 5tenths of a seconds now.



















The new muffler sells for from 55.00 to 28 dollars depending on the sourse and it it has thew spark screen. This aftermarket muffler also fits the Husky 357 and 359 and has the better cheaper pricesthan if you buy a Jonsered one. 

This saw might now get a bit more usage.

 Al


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## DaleK (Sep 23, 2004)

Nice. I have a new muffler waiting at the shop to be picked up for my 359 tomorrow, also have to get a couple bigger screws and tap them out where the old ones stripped.


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## Cabin Fever (May 10, 2002)

WOW! Never had a heat problem with my Jonsered. Are you sure the fuel/air was set correctly or top end rpm set too high? If the fuel isn't buring in the piston it can burn in the muffler making it red hot.


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## Nimrod (Jun 8, 2010)

Esplain this to me Lucy. I have never heard of a "cat" muffler. The first image that comes to mind is a cat with the exaust stuck up his butt. I imagine he makes more noise than the chain saw. Kinda defeats the purpose? 

Is a "cat" mufler some sort of union between a catalitic converter and a muffler? Was this chain saw sold for use in Califunny?

You are probably going to have the swat team at your door. You just admitted to breaking one of the EPA's laws when you removed the limiter cap on the carb so you could adjust the saw to run it's best. Do hang onto the saw since the new ones have no adjustments at all. You have to run it at whatever idiotic settings they dictate. 

Happy Motoring,


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## Madsaw (Feb 26, 2008)

Husqvarnas and Jreds with green fuel caps usually are catted. A cat muffler traps heat inside due to all the restrictions. So thwy heat up bad. Therefore nuttering the cat or switching the muffler you need to open up the high side. There is a good hp gain doing so.
Bob


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## foxtrapper (Dec 23, 2003)

Nimrod, a cat muffler is a muffler with a catalytic converter inside it. Mandated by the EPA not too long ago. 

They do run hotter than a non-cat muffler does. But just like on a car, they don't overheat unless the mixture is overly rich. It's a fine balance with these little high strung engines.

Lots of folk do pull the mufflers off and replace them with non-cat mufflers. Many claims of wonderfullness do exist. 

I've got a cat muffler on my Dolmar. Saw cuts just fine for me with it installed. It does tinkle and ping while cooling down after I shut the saw off. But, I've not modified the saw or tweaked the mixture overly rich.


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## defenestrate (Aug 23, 2005)

Much like recent cars, the newest cat-equipped saws and other small engine-powered implements will probably run better with the cat, but not if it's clogged.


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## Madsaw (Feb 26, 2008)

The idea of removing the cat does a couple of things. First the cat is used to increase exhaust temps to help burn off more emissions. So by opening up the muffler increase air flow through the saw. This will make them run faster. That will also make it run lean and hotter. That is why you must increase the fuel on the high side of the carb. This controls rpms and cools the internals of the engine. The new saws are set so lean due to emission plus the cat mufflers.
But with the new strato saws they can run no cats again due to how airis injected into the cylinder to miss with the fuel air mix. 
Dolmar mufflers are stainless steel. That is the reason for the pinging and popin. They have them saws running on the very edge of cooking to pass emission.
Bob


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## alleyyooper (Apr 22, 2005)

The Jonsred 2159T I have was sold in Michigan. It does have the green fuel cap too and there is some adjustments on the carb even with the limiters on. Like any other 2 cycle engine you read the plug color to make sure the air fuel mix is correct. If the plug is black it is to rich and if white your lucky it isn't fried.
If the exhust outlet was some place other than the back side top of the muffler It woldn't be so bad buit with the exhaust there it directs the hot exhust right up in the crack between the chain brake and saw top cover.

Here is one the owner moded and kept the cat intact. The out l;et was placed where the company engineers should have put it in the first place.



















Since the aftermarket Muffler in many cases are old stock Husky parts I just took the money route to fix the problem after two attemps to fix the org muffler.

:hysterical:Has the EPA been to your house to check the emmissions of your two strokes?

 Al


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## farmrbrown (Jun 25, 2012)

I've found that a hot, tired, sweaty, hard working man with a stern look on his face and a running chain saw in his hand, is a very effective deterrent to pesky government types with long noses.:grin:


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## Cabin Fever (May 10, 2002)

Never knew about a cat muffler either. My Jonsered has a black gas cap, so evidently I don't have a cat muffler and, consequently, doesn't have a heat problem. I learn something from this forum almost everyday. Thanks!


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## tallpines (Apr 9, 2003)

This post made me think about another cat and saw story I once heard.

How do you get a dead cat to meow?

Put it in the freezer.
Once its frozen good and solid, get it out of the freezer.

Using your Skill Saw, cut the frozen cat in half.

When that Skill saw hits the cat you will hear "Meeooow"!


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