Saw Dr.
Junk Collector
I would like to know this also
Husqvarna 44 Muffler mod?
- Thread starter Gareth83
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I would like to know this also
scott and saw dr: It is welded because I know what welding looks like and there is no way I can get a screwdriver or anything in to prise it apart.
woodyman: thanks for your response it now makes sense when looking back at your original pictures even though your muffler is different to mine.
what I have just done so far is drill a 9mm hole in the front the same as yours, an 8mm hole in the side and kept the existing. This is about 82% of exhaust port area
Once I have got it running then I will then either port each additional hole to 11mm and seal up the original giving 80% but also bypassing the silencer or port the front hole to 16mm and sealing up the other 2 which equals 85% and again bypasses the silencer.
Which of the above do you favor?
Looking back now I'm thinking that 10 smaller holes of 5mm to the front and welding up the original would have been easier and would also negate the need for a screen. what are your thoughts on that?
woodyman: thanks for your response it now makes sense when looking back at your original pictures even though your muffler is different to mine.
what I have just done so far is drill a 9mm hole in the front the same as yours, an 8mm hole in the side and kept the existing. This is about 82% of exhaust port area
Once I have got it running then I will then either port each additional hole to 11mm and seal up the original giving 80% but also bypassing the silencer or port the front hole to 16mm and sealing up the other 2 which equals 85% and again bypasses the silencer.
Which of the above do you favor?
Looking back now I'm thinking that 10 smaller holes of 5mm to the front and welding up the original would have been easier and would also negate the need for a screen. what are your thoughts on that?
woodyman
Addicted to ArboristSite
Which top cover do you have because that hole in the back might not exit right.
Maybe you have the open style top cover.
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Which top cover do you have because that hole in the back might not exit right.Maybe you have the open style top cover.
had me worried then lol, just grabbed the saw out the shed at 1am to check. It's similar to the first type but there is 1" clearance from hole to cover.
So I guess it will end up being a single port at the front with the side and original welded up lol.
What should I set the screws to on the mixture before I fire it up in the morning?
woodyman
Addicted to ArboristSite
I would leave the original and the one in the front.I would just start it up and adjust it so it 4 strokes at WOT and 2 strokes once its in the cut.
Bear in mind I know very little about tuning haha, one turn each from all the way in and then adjust from there?
Which top cover do you have because that hole in the back might not exit right.Maybe you have the open style top cover.
the hole in the side has caused part of the cover to melt through lol, so I will definitely get this welded up and just stick with a 16mm hole to the front.
I must say the saw felt a lot more powerful, certainly sounded a lot better anyway.
However the saw kept cutting out at idle, despite playing around with the L screw it still kept doing it.
The filter was cleaned the day before, however when I checked to see if it had clogged it was apparent it had worked it's way loose. i think I overtightened it and damaged the thread on the filter itself.
So ordering a new one today and may as well get a fuel filter also. How hard are these to change?
woodyman
Addicted to ArboristSite
Just pull the filter out of the tank with a long needle nose pliers,there are vids on you-tube on all stuff related to chainsaw maintanance.If you stripped the threads on the air filter mounting bracket you could heli-coil it or look on chainsawr.com they are a sponsor at the top of the page and have one for $3.50 plus shipping for a used one and othe parts for your saw.You don't have to tighten the air filter screw too tight.
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Gareth, my pre EPA Stihl 044 (70.7cc) saw has a .073" diameter exhaust outlet in the muffler. If your 44 (44cc) saw needs to have a 16mm diameter outlet in the front of your muffler I'd suggest that you put a spark arrester screen over it and have the other two holes welded shut. You still might not be able to properly tune the low end.
woodyman
Addicted to ArboristSite
Yeah I was thinking about heli-coiling the bracket but decided it could benefit with a new filter altogether. What's the difference between a flock and nylon filter?
i'll get a fuel filter also just in case it's a fuel issue as opposed to unmetered air
Yeah I'll weld up the original and my poor attempt at a side exit haha. This will bypass the silencer also so hopefully a little more power maybe?
I had one 5/8" straight pipe on mine and it idled and reved just fine with alot of power for a 44cc saw.
5/8" is more or less 16mm so I think I'll be alright then. Think I'll try and get hold of a 5/8" just to be on the safe side.
Thanks all
Saw Dr.
Junk Collector
Here is what I suggest:
Go get a bigger saw that makes all the power you need without mods AND A GOOD WARRANTY.
Seroiusly, 5 pages of reading, several good suggestions and here is what we ended up with:
2 scrap mufflers (neither of which are welded together)
1 scrap topcover with a hole melted in it
1 scrap air filter with stripped threads
1 saw that runs worse than when you started.
I support anyone who wants to learn, but you seem to have disregarded all of the valuable advice, and done what you wanted anyway. Let me ask you this: What happened to all of the shavings from the holes you drilled in that muffler? I suspect that several of them found their way inside the muffler. Lets hope none found their way back into the engine yet.
neutral4x4
ArboristSite Operative
:agree2:
Ok, before you dive into a project you should know what you're doing. Judging by what you posted it's clear you don't.
The first thing you need to understand is that air flow is restricted by the smallest diameter opening in a system. It is also hurt by sharp corners and anything that prevents a smooth flow over a surface.
Think of the path the gas has to follow in the stock muffler. The gases exit the exhaust port at the piston, flow through the cylinder port, and enter the muffler. You seemed confused as to the "at the piston" thing.
Here is a picture showing what they meant:
As you can see, the port at the cylinder wall (where the piston sits) is smaller than where the muffler attaches. You want to base all of your measurements off from the smallest part of the hole.
The inlet hole on your exhaust should be fine unless your engine has been ported. I'll assume you haven't tried that yet.
From there they enter the baffle (the thing with lots of holes in it that you can see right in the middle of the picture of your original muffler). You need to find the diameter of the holes, count how many they are, and find the total area of them. My guess is that these need to be opened up too. If you can't open them up without destroying the muffler, you should be able to cut a section out with your dremel. Just make sure you don't weaken the metal too much, because your muffler needs that part for strength when you tighten down the muffler bolts. The area of the diffuser holes won't matter much once it's above 85% of the exhaust port, but it needs to be at least 85 or it'll be a restriction to the system.
Next, the gases enter the exit pipe, which I assume is perforated on the side next to the baffle. That looks like the hardest part to overcome. If you have the capability to weld it up, do it. You have no idea how large or how many holes there are in that. If you can't, it'll be best to just assume that the area of the holes is the same as or larger than the outlet pipe. It's always better to err on the small side if you're unsure.
Finally, you have the gases that can't fit out your outlet pipe. They need to go somewhere. That's where drilling a hole on the outside comes into play. I would've drilled it right next to the outlet pipe on the front of the muffler. Make sure the hole brings you between the 80% and 85% mark.
As stated above, clean out the muffler well, or your engine is going to suck in a bunch of metal. A couple shavings in the cylinder and you'll have to start looking for a brand new saw.
Oh, and about the high idle part, make sure your muffler is bolted down tightly. If you have an air leak at the exhaust port, your engine will run fast at idle. If you let it go too long, you might run into some major problems.
P.S. Don't get mad at these guys. They're only here to help you. Most of them know what they're doing and have a ton of experience. Nobody is out to get you, but it can be frustrating when someone asks a question and then proceeds to disregard their advice. If you don't follow their advice, I recommend not crying to them when something goes wrong.
Good luck. And to everyone else, everyone was a noob once, try to take it easy on them. I'm sure there was a time when you had no clue what you were doing. Everyone has to start somewhere.
a) I don't really need a bigger saw, even a 35cc would be fine for my needs. I use it once a week if that simply for a bit of firewood.
b) I cannot afford (read justify) buying a brand new saw certainly not for my needs. My 80GBP saw will do the trick. I certainly don't mind playing around with it
c) The first was a scrap muffler anyway, did you not see the state of it? It was wafer thin, seriously rusted. Besides I needed to open it up to see what exactly I was playing with. It would be silly just drilling anywhere and drilling just next to the existing would not have worked.
d) The second muffler is not scrap, my mate is going to weld a plate on the side hole. No biggy is it? Trial and error! Had I drilled a side exit hole like woodyman then the silencer would have been in the way and this would have meant splitting the exhaust which brings me onto
e) Both were welded. FACT. I have both infront of me right now and two of my mates have both looked at it. It is a different design to woodymans hence all the questions.
f) the top cover is not scrap, it has an 8mm hole in it. It's not a sealed unit where the hole is so who cares?
g) scrap air filter because it's probably the original since the saw was new! I'm just the current owner so I have since ordered a new one for 10GBP
h) course it will run bad if the air filter is loose
:agree2:
Ok, before you dive into a project you should know what you're doing. Judging by what you posted it's clear you don't.
I admit I didn't hence all the questions. The FAQ suggests a simple hole is the easiest method which I was trying to determine where to locate.
The first thing you need to understand is that air flow is restricted by the smallest diameter opening in a system. It is also hurt by sharp corners and anything that prevents a smooth flow over a surface.
I know this which is why I couldn't put the hole directly in front of the silencer as suggested. My muffler is a different design to the ones discussed
Think of the path the gas has to follow in the stock muffler. The gases exit the exhaust port at the piston, flow through the cylinder port, and enter the muffler. You seemed confused as to the "at the piston" thing.
I wasn't confused. My port is not tapered like the below picture. So I knew what I was talking about
Here is a picture showing what they meant:
As you can see, the port at the cylinder wall (where the piston sits) is smaller than where the muffler attaches. You want to base all of your measurements off from the smallest part of the hole.
I know this, see my above point
The inlet hole on your exhaust should be fine unless your engine has been ported. I'll assume you haven't tried that yet.
From there they enter the baffle (the thing with lots of holes in it that you can see right in the middle of the picture of your original muffler). You need to find the diameter of the holes, count how many they are, and find the total area of them. My guess is that these need to be opened up too. If you can't open them up without destroying the muffler, you should be able to cut a section out with your dremel. Just make sure you don't weaken the metal too much, because your muffler needs that part for strength when you tighten down the muffler bolts. The area of the diffuser holes won't matter much once it's above 85% of the exhaust port, but it needs to be at least 85 or it'll be a restriction to the system.
There was no need to open them up, plenty of area
Next, the gases enter the exit pipe, which I assume is perforated on the side next to the baffle. That looks like the hardest part to overcome. If you have the capability to weld it up, do it. You have no idea how large or how many holes there are in that. If you can't, it'll be best to just assume that the area of the holes is the same as or larger than the outlet pipe. It's always better to err on the small side if you're unsure.
Finally, you have the gases that can't fit out your outlet pipe. They need to go somewhere. That's where drilling a hole on the outside comes into play. I would've drilled it right next to the outlet pipe on the front of the muffler. Make sure the hole brings you between the 80% and 85% mark.
As stated above, clean out the muffler well, or your engine is going to suck in a bunch of metal. A couple shavings in the cylinder and you'll have to start looking for a brand new saw.
Oh, and about the high idle part, make sure your muffler is bolted down tightly. If you have an air leak at the exhaust port, your engine will run fast at idle. If you let it go too long, you might run into some major problems.
P.S. Don't get mad at these guys. They're only here to help you. Most of them know what they're doing and have a ton of experience. Nobody is out to get you, but it can be frustrating when someone asks a question and then proceeds to disregard their advice. If you don't follow their advice, I recommend not crying to them when something goes wrong.
Good luck. And to everyone else, everyone was a noob once, try to take it easy on them. I'm sure there was a time when you had no clue what you were doing. Everyone has to start somewhere.
muffler cleaned out with a vacuum and blown with an air compressor
Gareth, if you would of drilled a hole next to the outlet hole (above, below, front, or back) it would of increased the area to let the backpressure out of your muffler. Can you understand that ?
agreed, but I calculated I needed an additional 11mm hole over and above the original to meet the 85%
What I was saying that I did not know the location of the silencer, having opened it up there is no way I could have drilled an 11mm hole above this without hitting the silencer.
Had I hit the silencer it would likely be rattling around in the muffler as it is only held on by a small spot weld internally. I did not wish to open up the new exhaust particularly as it is definitly welded and still did not come apart even when I cut all around the original
As woodyman states his saw ran fine with just a hole at the front
I doubt that if you would of started step drilling the area above the existing outlet that the spotweld would of been broken. If you would of drilled a single 1/4" diameter hole above the existing outlet I'd bet it would not of broken the spotweld. You could of used a file or your new Dremmel with a stone on the corner to open the area above the existing outlet if you thought that the drill bit would break the spotweld. Is the silencer spotwelded to the baffle on the original (rusty) muffler?
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