Picked up a husqvarna 40, wont run with muffler on.

[Tinman204]

So I picked up a super clean husqvarna 40 from a guy in the city yesterday for $20.

He said it ran fine until a month ago and then it wouldn't start.

He said it had no spark.

I took it home and found as I suspected that the coil contacts were covered in bar oil and weren't getting a signal from the flywheel.

Cleaned them off, inspected the carb, pulse line and piston. Compression is great and piston is like new.

I pulled the saw over and it fired right up. I adjusted the carb as it was running off.

The saw sounded weird, the muffler is almost hissing and rattling and the saw is slow to rev.

The muffler has no screen in it so I ruled that out quick. After a couple hours of mucking around I pulled the saw over with no muffler and It fired up with authority and ran perfect.

I made a couple of cuts with it and it had tons over power and ran fine with no muffler.

I put the muffler back on and it runs boggy again and lacks power.

Could the baffles be clogged?

Maybe I should do a muffler mod on it?

Any thoughts?

I've had clogged screens but never a restricted muffler.

 

[Ozhoo]

Mud daubers have taken up residence.

 

[s sidewall]

Put it in a fire and Burn it out

Steve

 

[Tinman204]

Put it in a fire and Burn it out

Steve

So you recon the muffler is plugged with carbon?

I kinda figured that but the muffler is so closed up that I cant see inside.

Thabks for the tip.

 

[s sidewall]

Cheaper to burn one out than replacing. Just blow it out real good.

Steve

 

[Sam R]

I usually use a butane torch, blast it, tap out what I can and then compressed air once it's cool enough to not blow hot fragments all over.

 

[Huskybill]

On my husky 240 the spark arrestor was clogged solid with carbon. I took a needle the poked it clean. On this muffler I could see the screen.

 

[Tinman204]

This one has about a 1/2" outlet that has clone with thin slots all around. It's a very restrictive design to start with so I'm guessing if it is clogged that would be a reason why it wont run right.

On a positive note I tried a cold start after letting it sit a few days and it popped 2nd pull on full choke and fired up on the 3rd pull.

It wont idle with the muffler on and its lazy so I'll have to investigate that muffler this weekend for sure.

 

[Tinman204]

So after burning out the muffler in a fire it still wouldn't run right.

I pulled the saw right down again and found the pulse line grommet was deformed, and also that the intake gasket was suspect. I also decided that perhaps the diaphram in the carb may be an issue.

Ordered a carb kit and replaced the fuel line and filter. Replaced the impulse line and grommet and rebuilt the carb. That plastic intake threads where the carb bolts up felt a little stripped on one side so I repaired the hole with epoxy and retapped the threads.

I then resealed the intake with a new gasket and some gasket maker to make sure it was sealed.

Then I did a muffler mod as I still suspected the muffler was a problem.

Saw starts 2 pulls cold now and and pull warm. I'm actually surprised how much grunt this little plastic homeowner saw has!! Its been great for limbing around my 14 acre property where I often walk and carry my saws.

I was going to sell it but it's so minty and light I figured I'd put it on the shelf and ponder whether I'll keep it or not.

Hard to part with a good running saw that I'm into for $26 canadian!!

Thanks for all the help guys!!

Can anyone tell me the year based on the tag??

 

[Ozhoo]

Can anyone tell me the year based on the tag??

2nd week of August 1985

 

[Tinman204]

2nd week of August 1985

Thanks, pretty minty for being 30+years old I'd say.

 

[smokey7]

Nice that you got it running well. So what do you think actually fixed it? The carb kit/intake gasket, impulse gromet, or the muffler? It seemed like you narrowed it down to muffler before. What was actually in the muffler? Did you just add a second port before the baffles? Thats one bad thing about doing multiple repairs at the same time..... You never really know what fixed it. Same with porting if you move the transfers lower intake and advance the timing at the same time. You just dont know what made the gain you were looking for.

 

[smokey7]

Also if you like the 40 so much keep your eyes out for a husky 42 or 242. Just about the same weight maybe the 42or242 could be lighter but a pro style saw with way more revs and power out of the same size package.

 

[s sidewall]

Saw looks real nice, glad you got it running.

 

[Tinman204]

Nice that you got it running well. So what do you think actually fixed it? The carb kit/intake gasket, impulse gromet, or the muffler? It seemed like you narrowed it down to muffler before. What was actually in the muffler? Did you just add a second port before the baffles? Thats one bad thing about doing multiple repairs at the same time..... You never really know what fixed it. Same with porting if you move the transfers lower intake and advance the timing at the same time. You just dont know what made the gain you were looking for.

I pull wrenches much better then I form sentences and explain things lol!!

I did 5 repairs to this saw. Each made it run better and together they made it run perfect.

First I cleaned the magnets on the flywheel and the contacts on the coil. That made it start but it was lazy.. could only get it so far with tuning.

Then I opened up the baffle in the muffler which instantly gave it more throttle response and more power. Still need to braze a new outlet into the hole in the muffler but it runs good enough for now even if it looks ugly.

The impulse grommet was suspect although I couldn't get it to leak it looked questionable. Being a stihl guy I was unfamiliar with this style of impulse setup, once I saw a youtube video on the fleet command channel about those impulse grommets I soon figured out that this one was no good. So I replaced the impulse grommet.

The carb kit made it start, run and tune easier so that helped. The carb originally had dirt in it but cleaning out what I could see didn't yield results until I pulled the Welsh plugs and gave it a deep clean. Then it ran very well.

Lastly the intake was suspect so I resealed it with gasket maker and a new gasket. Fixed 1 carb bolt which wasn't getting tight enough.

Doing each one of those repairs netted a positive result.

Its was one of those engines that on the surface was going to be an easy repair (getting spark) but then after needed many small things to make it perfect. I would of cost a fortune for the previous owner to have it repaired at a shop.

I've been buying saws to learn and this one gave me huge learning time for no money. And resulted in having a useful tool at the end which is a bonus!

 

[s sidewall]

Never know what shape a saw is in until you get into it, saw should serve you well for a good while.

Steve

 

[Wood Doctor]

I just serviced a Husky 40 that I sold last year to the owner of a tree removal company. His nephew somehow wore out the sprocket and had managed to install the wrong chain. After I fixed it, I offered to buy it back for what his uncle paid for it. He said, "No entire way! I'm keeping this saw."

Dang, I'd like to run it again. It pulls its 18" bar and chain without a complaint. However, I think Smokey7 is right on the money in post #13, but finding these saws is like finding a needle in a haystack.