Husqvarna 44 Tuning help

[rjm240]

I am trying to figure out the problem I am having with my old Husqvarna 44 holding a tune. Both my brother-in-law and myself have spent several hours adjusting the saw, going back to stock setting and then adjusting again. Just about the time it seems right you go out the next day and it will not run again. We got fed up enough and bring it in to a mechanic to have it adjusted. Even that didn’t help much.

As it is currently set up the saw starts and idles great. 1 pull with the chock and high idle, it will grunt. Push the choke in and it fires right up. Then let it idle a minute to warm up and it runs like it should. It even makes a couple of cuts then eventually starts bogging in the cut. Pull it out of the cut and it idles fine but try cutting again and there is no power and the saw bogs.

I did a little searching today and it seem like the tank vent could be a issue but I don’t remember any improvement after removing and reinstalling the gas cap. I can check that tonight.

What else could it be? Any other things I should check or re-check?

 

[rjm240]

Here is a photo of the saw.



Sent from my Nexus 5 using Tapatalk

 

[rjm240]

This thread might turn into more of a blog if I am the only one talking here.


I spent an hour or so going over the saw. I pulled the muffler to check the P&C. They both looked very clean and no scoring. What should the ring look like? I could barely tell it was there and it was roughly the same color as the piston, chrome/shiny. I expected it to be black. I do not have a compression tester but it starts great, idles ok and seems to have power so I do not think I am having troubles with the power cylinder.


I also took the carb off again and sprayed through all of the passages. I took the adjustment screws out and sprayed through the holes to see if any gunk was hiding in there. I put it all back together and it still runs the same.


Starts and idles fine, but is very hard to get to “hold a tune.” I started by setting the H 1.5 our and the L at ¾ out. I then adjusted the L to get max RPMs. Then held it wide open and it two stroked scary so I cranked the H out a bit, maybe another turn. Then it won’t idle so I had to crank the L back in. When I do that it bogs when I give it gas and doesn’t have as consistent of an idle.


Why is the H adjustment impacting my L? Should I go on Ebay and do a whole carb kit?


This part seems a bit hard and stretched but is not ripped. Potential issue?

 

[wcorey]

Lots of possibilities for this kind of issue, these three are the most likely to affect fuel/air mixture;
Carb rebuild is easy and might cure it, the part you picture is the metering diaphragm and that it's not pliable is a good indicator that it's time has expired.
Also check the fuel line for cracks/deterioration and if the fuel filter is flowing well.
An air leak is also a good possibility, you need to do (or have done) a vacuum/pressure check.

Quick check for the tank vent is to crack open the cap when it's running bad and see if that fixes it temporarily.

If it's none of the above then there's a new list of things...

 

[rjm240]

I am quite sure it is not the tank vent. Opening the cap has no impact and I blew, with my mouth, through the vent tube and gas came flowing out of the fuel line. It did not take much blowing. I would expect this blowing would also prove the filter flows fuel.

The fuel lines are a bit hard to see, as they are tucked in above the fuel tank. I can take a light to them and check them over again.

I have never heard of a vacuum/pressure check. I will have to search it a bit and write back.

I might just do the carb rebuild. It looks like a kit is <$15 on Ebay. The saw is shiny and clean now and I sharpened the chain, to learn how.

 

[rjm240]

Just thinking. My dad gave me 2 husky 44s. One runs better than the other but leaks oil like crazy. I wonder if I can just swap the carb over from the running saw. I will look tonight. One is a 1975 model and one is a 1987 model so might be a different carb.

 

[svk]

I'm surprised you haven't received more responses.

Try swapping carbs to see if it solves the problem. I'm betting it will.

 

[zwoehr]

Those seem like big adjustments to the screws to me. I usually only have to turn them less than 1/2 a turn from the default settings. When you do the L screw try to find the spot between the fastest idle and when it starts to slow down. Adjusting for fastest idle might make it run too lean. Also if that diaphragm is hard it should be replaced. swapping carbs with a known good runner will definitely tell you something.

 

[rjm240]

Agreed, I can make significant turns to either the H or the L with minimal impact on saw performance. I am just thinking here but maybe both the H and L circuits are open at idle. That could be why, when i first set the tune it runs ok, but then when I richen up the H to get 4 stroking it floods out at idle so I have to turn the L back in. Then it bogs because the L is too lean as the H isn't kicking in fuel consistently at idle. I am guessing that vacuum pulls the metering diaphragm and the needle to open the H circuit. If mine is hard potentially it is always holding the H circuit open, at least part of the way, and causing my tune issues. I will let you guys know if the other carb fits

Remember this saw just had its 40th birthday. It did have the switch replaced about 10 years back. My dad bought it new to clear the land for the house I grew up in. The P/C have never been out. He cuts 4 cords a year and this was his only saw until about 10 years ago. I wouldn't say he over maintains his saw but he has always used good fuel and good oils.

 

[7sleeper]

hello rjm240 ,

I posted in your other thread also.
http://www.arboristsite.com/community/threads/need-help-picking-first-saw.284983/page-3
What you describe as being a little "hard and stretched" is the carb membrane. To be clear carb membranes are usually NOT hard and stretched => it needs to be replaced to run correctly! As I mentioned in my other post, renew all "rubber" parts (fuel lines, carb membrane, etc.) and you will have a litterly "new" reliable saw again. Those saws look hardly used and by the look of the cylinder they sound really worth repairing!

7

 

[Chainsaw Jim]

When a carb doesn't hold a tune it needs rebuilt. Go out and buy a kit for under $15 and replace both diaphragms and gaskets and you'll be able to tune it correctly.
Don't use ethanol fuel to prevent this from happening again.

 

[Rockjock]

I have 44 much like yours and IIRC it was 1 turn out on both. I suggest you get a carb kit or a known to be working carb and try that. Mine came to me with 15 years of crud caked on the recoil like cement so as to mimic that it was seized. A good clean up an it is running like a champ. I do thik it feels intimidated by all the stihl saws I have but it holds its own!

 

[dbittle]

I had a similar situation on a 242xp and it turned out to be that the crank seals had fossilized. They are neoprene so they will harden over time. I agree that you need a carb kit, and second the advice that you do the vacuum/pressure test. Alternatively, you might just add the seals and a new fuel line to the carb kit order and replace them as wear items.

 

[rjm240]

I didn't have a chance to swap carbs. It got to late and I didn't want to wake the kids. It does look like swapping will work. The carbs have a different choke linkage but everything else is the same.

When apart I noticed the original saw in question had much less tension on the metering diaphragm than the saw that runs better. So I took it apart. I found that the spring was a little cockeyed that holds the needle closed under the metering diaphragm. This put less pressure on closing the needle, potentially opening the H circuit with idle vacuum. Not to mention the stretched metering diaphram.

I see the carb is a walboro HDC. Is there anything else I need to know before ordering the kit. I noticed the kits don't contain a new spring so I will have to work mine back into shape.

Sent from my Nexus 5 using Tapatalk

 

[rjm240]

Sent from my Nexus 5 using Tapatalk

 

[7sleeper]

@rjm240 ,

I will again repeat above comments and myself to try to make it clear again. As long as you DONOT replace the "rubber" parts, it is highly unlikely that you will achieve more than a hack repair waiting for desaster! I have the impression you are trying to save money in the wrong area. ALL "rubber" parts dry out over the years and deteriorate. To be clear I doubt you would intend to drive on a german autobahn full speed with 40 year old tires! That is what you are trying at the moment and to be honest, I see desaster right around the corner. As I mentioned in your other thread if you invest a minimum you will have two good working saws again for very little money! Carb membranes @ ~15$, generic(not sure generic will fit on your model but highly likely) TYGON fuel lines @ ~5$, crank seals @~ 25$ and voila a great starting point for the future!

good luck!

7

 

[Chainsaw Jim]

@rjm240 ,

I will again repeat above comments and myself to try to make it clear again. As long as you DONOT replace the "rubber" parts, it is highly unlikely that you will achieve more than a hack repair waiting for desaster! I have the impression you are trying to save money in the wrong area. ALL "rubber" parts dry out over the years and deteriorate. To be clear I doubt you would intend to drive on a german autobahn full speed with 40 year old tires! That is what you are trying at the moment and to be honest, I see desaster right around the corner. As I mentioned in your other thread if you invest a minimum you will have two good working saws again for very little money! Carb membranes @ ~15$, generic(not sure generic will fit on your model but highly likely) TYGON fuel lines @ ~5$, crank seals @~ 25$ and voila a great starting point for the future!

good luck!

7

Reeeeelaaaaax man. Those crank seals last a bit longer than fuel lines and carb kits. Besides....why spend $200 to repair them at a shop when it's a $100 chainsaw? Isn't this where you fix it for $15-$20 and run it until it dies and then spend that $200 on something newer and better?

 

[Chainsaw Jim]

I didn't have a chance to swap carbs. It got to late and I didn't want to wake the kids. It does look like swapping will work. The carbs have a different choke linkage but everything else is the same.

When apart I noticed the original saw in question had much less tension on the metering diaphragm than the saw that runs better. So I took it apart. I found that the spring was a little cockeyed that holds the needle closed under the metering diaphragm. This put less pressure on closing the needle, potentially opening the H circuit with idle vacuum. Not to mention the stretched metering diaphram.

I see the carb is a walboro HDC. Is there anything else I need to know before ordering the kit. I noticed the kits don't contain a new spring so I will have to work mine back into shape.

Sent from my Nexus 5 using Tapatalk

What are the numbers on the side of the carb?

 

[rjm240]

The side of the carb reads: HDC
32 A
7/80

The bottom of the carb reads: 21-146

 

[7sleeper]

Reeeeelaaaaax man. Those crank seals last a bit longer than fuel lines and carb kits. Besides....why spend $200 to repair them at a shop when it's a $100 chainsaw? Isn't this where you fix it for $15-$20 and run it until it dies and then spend that $200 on something newer and better?

I am relaxed, but you seem a bit tense... Crank seals lasting 40 and 28 years???

...One is a 1975 model and one is 1987....

Well ok maybe, but personally I wouldn't take a chance because of ~15 - 20$ replacement for both sides. And why spend 200$ at a shop when one can do it usually easily oneself? Just like replacing fuel lines and installing carb kit. That is why I mentioned above prices and NOT repair shop prices! And with what I mentioned above one would have, highly probable, two well running saws for way less than 100$! With the replacements the saws would be good to go again at least another decade! Especially with this estimated yearly runtime

...In total I estimate engine run time to be 10 hours a year...

And does anyone really believe that modern saws will outlast these older designs... Last please show me quality saw for 200$ that is in perfect condition in the same power league...

7