Husqvarna 128LD Muffler Mod

Did this mod about 2 years ago

[@n5yiz]

I was calling "BS" on this mod until I went out to the garage and tried it. Took me about 15 mins and the blower has never run better. It was just about impossible to tune at sea level and had never run right since I bought it. Thanks!!!!!! This was done on a 125B

[@crazyjdkid]

It definitely smoothed mine out a bit, not sure why the hole was so small to begin with! Thanks for watching and glad it worked!

[@alohadakine4571]

This mod works, I have the EXACT same model (Husqvarna 128ld) I did this mod exactly as shown (took the muffler out then took my drill to it w metal bit) will cool your motor faster & increase power. My damn motor used to get hot fast, now it runs hella cool, impressively cooler.

[@crazyjdkid]

+V3RITY VLOHV Yeah it works pretty well! Thanks for watching!

[@79firebirdman]

That 'mod' does little in the way of true performance improvement. I have had one of these weedeaters ten years and a few years back, right around the time the warranty expired, i did this same exact mod to it as well as opening up the deflector on the front of the muffler. Fast forward to recently, and I noticed the weedeater bogging down and having greatly reduced power and I thought the fix would be to tweak the high speed jet setting a bit. Long story short, I discovered that the muffler has a catalytic converter which I would have removed long ago had I known it was there. The catalytic converter is made of tightly packed steel wire and is located directly underneath the spot on the muffler that has been discolored from high heat. This catalytic converter evidently gets clogged with carbon deposits over time, and would not have been very free flowing when new. Call it the weedeater's timed self destruct feature because that's what it is: its only conceivable reason for existence is to drive sales of new units. The only option to fix---eliminate!---the problem is to uncrimp the muffler and remove the cat, as there is no way to drill and bypass it without completely ruining the muffler. There is a baffle surrounding the catalytic converter, which you will have to drill the corner out of, then remove the steel wool with wire pliers and needle nose pliers. Once this is done, leave the baffle in place and clean the carbon out of the muffler parts and ports and drill as needed so that exhaust passages through the muffler to the exhaust outlet on the muffler are around 80% of engine exhaust port size, along with any needed port matching of the muffler inlet and engine exhaust port. Reassemble the muffler and re-crimp the muffler halves using a ball peen hammer. Reinstall the muffler and cut the exhaust deflector open so that there is only enough of it left to hold the spark arrester in place, then cut off the plastic ribs directly in front of the exhaust outlet, as the exhaust now flows straight out of the muffler. Cut only the three or 4 ribs in front of the muffler exhaust outlet, DO NOT cut the structural parts of the plastic muffler housing as this housing helps directs flywheel fanned air around the engine for cooling and is a critical part that should not be damaged or removed. After everything is re-assembled, readjust the carburetor high and low speed jets and idle speed setting as needed to enrich the fuel mixture so that it will not go lean at high rpm, because the weedeater WILL now run at higher rpm. IIRC, ballpark on the high speed jet is 1/2 to 3/4 turn out and no more than 1/4 turn out on the low speed jet with minimal idle setting change. When it is correct there will be a slight miss at WOT with no load and this miss will disappear when laying into a heavy weed patch or tall grass and will smoke ever so slightly on acceleration from idle to WOT. Or, tune it with a tach, if you're not knowledgeable or comfortable with the procedure for tuning a two stroke motor by ear. Yes, this mod takes some time, effort, and mechanical ability, but it is very well worth it, because the 128LD will now run and operate completely different.

[@curt32807]

Interesting mod! Think Ill give this a try. Do you keep the access plate on after the mod?

[@crazyjdkid]

Yes! I did!

[@crazyjdkid]

Thats good! It made mine run a lot cooler!

[@Superthecod]

I did it! it runs so much better

[@Superthecod]

I think I'm going to do it this weekend, so you don't have to do anything else besides drill holes?

[@silverdragontaylir8252]

Genius, Genius,,Genius (I was about to throw it away),I'm going to use die grinder(cut slot)

[@bernardosuarezcretton622]

hi there. in terms of power gain. how many HP do you think earned by Muff Mod? 0.5 HP up to 1 HP? in chainsaws this is a standard gain. Greetings from Argentina

[@user-neo71665]

This thing is only 1.1 horse factory. If it makes any more it's gonna be like a 1% increase.

[@CalBearTactical]

Do you think this muffler mod will work with the 323L also?....my warranty isn't done yet with my 128LD, but my 323L is.

[@crazyjdkid]

Nope! Just don't let the shavings get into the engine though, and dont drill them too large!

[@newwavepressure6478]

Do u have to adjust the carb after the muf mod

[@crazyjdkid]

I didn't have to!

[@iixlegitgamer]

Sweet might have to try this thanks forthe tip

[@caseymistry]

my exhaust muffler has lot of oil accumulation , what could be problem ? Any advice

[@crazyjdkid]

First and foremost, make sure you are using a 50:1 ratio and a high quality gas and oil. You might be running it a bit too rich. Oily mufflers are pretty common on a lot of two strokes. I would remove the spark arrestor if you can to prevent future issues. A lot of short run times can lead to this as well, go work it hard and get it hot to burn some of it off. Thanks for watching!

[@caseymistry]

After removing spark arrestor do I put the plate back with 4 screws ?

[@crazyjdkid]

+casey mistry Yes!

[@caseymistry]

Thank you, I will make holes as mentioned and will see

[@dbezzy45]

Same, it's oily on mine as well.

[@JohnDeere50d]

Will this work with a 4 cycle trimmer

[@crazyjdkid]

I would have done it earlier but I didn't want to screw up the warranty.

[@user-neo71665]

Get more results from uncrimping the muffler and removing the cat.

[@owentimo]

Did you re-adjust the carb for the engine now being too lean?

[@crazyjdkid]

Not immediately no, ran fine without adjustment.After like 4 years I did adjust it a bit.

[@owentimo]

Thanks. I just did it late last night along with installing a new carb. I will let you know how it runs...

[@TheSonsOfSimon]

Sparta how did it work? Mine has run bad since it was new...

[@owentimo]

@@TheSonsOfSimon Sorry I didnt see this. Its still running 100% great. I still use the premixed fuel and runs great year after year.

[@crazyjdkid]

Not if you still have warranty.

[@TheWallyjp]

ya i find mine does run hot but i dont mind

[@crazyjdkid]

no prob.

[@gravely86]

Should I do this 2 my 128cd

[@Zicwidit90]

Hey man I've got the same weed eater and have done this mod recently thinking it would help but hasn't. When im using it it runs great but when i left off the throttle and just let it idle it dies or wants to die until i hit the throttle again, any advice?

[@crazyjdkid]

+oscar arias Sounds like it is not properly tuned or it has a dirty carb

[@Zicwidit90]

+crazyjdkid thanks for the reply man, think im going to take apart the carburetor and clean it. It's a start i guess and doesn't cost me a thing to take it apart.

[@crazyjdkid]

Yeah! you could try just spraying it off with carb cleaner.

[@owentimo]

I had to replace my carb with a new one from Amazon for $27. It would only run with half choke. Very easy to replace. You may have to adjust the idle screw on yours if it runs ok with the choke open. Do not run ethanol fuel in these if possible. I buy the premixed fuel at the store and it will last a long time.

[@charlescoker7752]

@@owentimo Now the honest Mechs tell you to use the premix. The oil gas mix even with non ethanol fuel still messes up the diaphragm. The gas is the problem benzine in the gas is one of the major culprits. That messes up the rubber.

[@crazyjdkid]

a little bit louder, not by much though

[@Allamut2909]

i can't find original husqvarna oil for it do you know what kind of oil it need? Full synth/mineral etc

[@crazyjdkid]

Any two stroke oil will work as long as it is mixed 50:1.

[@Allamut2909]

instruction say 50:1 2% ratio is for original husqvarna oil for all other 33:1 3%

[@crazyjdkid]

I dont thinkk so, just because of how they work with valves.

[@Superthecod]

make it any louder.