muffler mod on a poulan pro

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petordragon

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I came to this site to see how to tune the carb and have seen alot about muffler mods on here. Saw is already running much better. Have seen several pics of better saws on here and where to drill. here are some pics of the muffler on a cheap lowes saw is it worth porting?:chainsaw: the second one is with the screen on.
 
Petor , did you mean 'porting' the cylinder or porting (modding) the muffler?
Two totally different things.
The pics seem to show an unmodified muffler. If that's the case definitely open that muffler up, but don't forget to retune the carb.
Search "muffler mods" and you'll have enough reading to keep you busy for weeks.
The bottom line is that most modern saws, homeowner grade or pro grade will respond favorably to muffler mods. The EPA has mandated changes to saws, to run cleaner(leaner) this is done through carb settings and
restrictive exhausts.
Open up the muffler and re-tune the carb and you will free up power,
plus the saw will run cooler (less heat retained in the muffler).
CSW
 
stock muffler

yes I was talking of opening up the muffler. The questions I have is?
1. do I open the ports under the deflector or on the flat area around the part number. 2. do I use the deflector? 3. do I use the screen? I assume screen is to lower the chance of causing a fire, keep trash out of muffler and deflector is to turn exhaust away less you have to breath. Do they do anything else?:confused: Basically looking for someone elses trial and error results with this particular muffler.
 
I did one of those once, but don't remember what exactly I did to it. I know I ground out those slots and deflector but seems to me there had to be some drilling out of the inner baffle also.

I'll try to remember and get back to you. It was a real improvement so it's worth doing for sure.
 
If you know how to weld or braze, add a half inch piece of angled pipe to the side of the muffler like Lakeside shows in his muffler mod sticky at the top of the saw forum. If you dont want to weld or braze, you can drill a couple of 5/16 inch holes in the front of the muffler.

While you have the muffler off, drill out the baffle area inside the muffler where it meets the cylinder port. The screen is there to help put the sparks out. All engines will throw small pieces of ash or carbon from the fuel/oil. If you use a screen it will lessen the port size by half. Dont exceed 80% of the cylinder exhaust port area with your muffler mod and all should be well.

Those Poulan's are fun to hot rod! Good luck with it and make sure you open up your carb jets when your done with the muffler. The jet closest to the cylinder is the low side of the carb. Open both jets up by giving each a good a full turn counter clock wise once you pop the limiters off with a drywall screw. Make sure its running rich and four stroking well at the top of the rpm band until you get a feel for whats going on with the engine.

Best wishes,
Bob
 
pulled muffler off and found this. pulled shaft out of muffler which allows it to bypass put small washer on the bolt without the shaft so bolt would tighten and put everything else back on. Will this be too much?:confused:
 
The problem with taking those "shafts" out is you completely remove all the support for the outside of the muffler and all the weight of the muffler is now on that thin backside of the muffler. I'm sure it will crack and brake in a short time.

I do now remember that I drilled the "diffuser" in the center of the muffler out from the opening in the back of the muffer.

Hard to do, as you have to drill at a angle, best to start in an existing hole and progress to bigger holes. Then grind out the slots in the front of the muffler and drill the plates behind them.

You can also drill a hole in the deflector plate for a second opening.

Don't forget you have to enrichin the high speed carb screw to increase the fuel in the carb.

If you don't have the special tool for adjusting the splined screws I would suggest obtaining one.
 
tried it out started real easy low side only needed slight adjustment if any already sounded better but not much louder. opened it up and started feeding it more fuel till it started drown and let off it died. turned screw in half a turn 4 pulls latter it started (i was starting to worry) then finished fine tuning . It sounds better on top end and a bit louder. Tried it out on the same log trying to bog it down (keep in mind it has a safety chain) it tore through the log where it would have bogged down before and sounded much stronger. Will not know for sure till I go cutting again but the gains seem to be impressive. It is probably a little on the rich side on top end but I really don't want to burn it up.:chainsaw:
 
Anderson MO. I left one shaft in will that be enough don't want to tear anything up or should I go back to work? The baffle in the center is against both sides of the muffler.
 
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I would say this is probably as good as this saw will get without major modifications to the air filter box. I can't see it getting much air through that card type filter. It does start very easy and run and cut well thanks for all the help.
 
Sorry, I was wrong, the one I had out there was a 2 piece muffler case.

Like I said its a pain on the one piece but the diffuser can be drilled from the back side.

Running only 1 tube spacer (shaft) still bothers me some. One other option would be to cut some slots in them so there opened up but will still support the outside edge of the muffler.
 
My idea being I still have warranty left on the saw and it would be no trouble to put the shaft back in and turn the fuel back down on low side it was almost 3 full turns ( seems like alot to me) and little more than 1 full turn on the high side before messing with the muffler. It ran weak when I first got it but once it was broke in squeezing the throttle wide open all at once it would bog down and die if you didn't work it. cutting with it I had to constantly back off the log to get the rpms back up. It cut all the wood we need for the winter therefore paying for it self. For the price I paid for it will probably only last a couple more seasons any thing more than that makes it a great buy. I will keep a close eye on the status of the muffler but right now everything still looks brand new but I've only cut 7 ricks with it.:greenchainsaw:
 
You might be able to locate a cheap but useable muffler on fleabay to mod that will fit on there. I just bought one recently for the same reason figuring that if it didn't work out, I could put the original back on. As a matter of fact, the one I'm working on has more seriouse issues than I was aware of when I started and if I don't get it going, I may have two good used ones available. I think it is the same one that fits your saw.

Steve
 
Here's the one my kid did on his little 2500 that I put together from a couple of give me's for free.

He brazed it, but I would have welded it. Made a completely different runner out of it. In fact it's one of his favorite's for limbing with, even with all of my saws he has to choose from.

attachment.php
 
67 Mustang said:
You might be able to locate a cheap but useable muffler on fleabay to mod that will fit on there. I just bought one recently for the same reason figuring that if it didn't work out, I could put the original back on. As a matter of fact, the one I'm working on has more seriouse issues than I was aware of when I started and if I don't get it going, I may have two good used ones available. I think it is the same one that fits your saw.

Steve
Click to expand...

Steve, that's a good idea. My guess is that Petordragons saw is a PP4218 or similar. Why not give us the model number of your saw and we can recommend a pre EPA muffler.
 
My saw is a Craftsman 358.360360 which is either 36cc's or 38cc's, so it would be a 3816 Poulan equivalent. But I think the mufflers are all the same. It isn't pre EPA. Still have to work on it, but you'll have the old one to fall back on if it doesn't work out. I always try to build in a little redundancy and happened to locate this one cheap. It was in good shape.

Steve
 
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