Parting Out An Old Chainsaw

[PANDEMICBANDIT]

Do you see fuel in the lines as you try to start it? Is that a primer bulb just above the fuel filler cap? If so, have you pumped it a few times to prime the lines and carb?
I don't believe that saw has a reed valve. Looks good btw.

Do you see fuel in the lines as you try to start it?

Yes, I see fuel going through the lines and into the carb.

Is that a primer bulb just above the fuel filler cap? Yup

If so, have you pumped it a few times to prime the lines and carb?

I did, and its still a no go.

 

[PANDEMICBANDIT]

Try turning the carb H and L screws out another half turn if you haven't already done so..

Yeah, I did both your methods, there isn't even a sign that it wants to start.

 

[grizz55chev]

Yeah, I did both your methods, there isn't even a sign that it wants to start.

Just for the record, your saw in running condition is worth about $50 to $75 bucks. It’s worth far more as a learning tool to practice on. Whenever I have a hard starting saw, I have a checklist I go thru to get things going, compression, spark , fuel. Spark is not the issue so it’s either fuel or comp ( or vacuum leak? ) . You need good comp to draw the fuel into the carb, it’s what drives the fuel pump in the carb. Without going back thru the thread, have you done a pressure- vac test?

 

[Acornhill]

That carb is for the other style Poulan saw, it may be an issue on how the lines are ran, you did say if you drip fuel in the carb it will fire correct?


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[PANDEMICBANDIT]

Just for the record, your saw in running condition is worth about $50 to $75 bucks. It’s worth far more as a learning tool to practice on. Whenever I have a hard starting saw, I have a checklist I go thru to get things going, compression, spark , fuel. Spark is not the issue so it’s either fuel or comp ( or vacuum leak? ) . You need good comp to draw the fuel into the carb, it’s what drives the fuel pump in the carb. Without going back thru the thread, have you done a pressure- vac test?

Yeah, thats the gamble with buying really cheap chainsaws for under $30. It may have a few small problems that are easy to fix or big problems that cost to much to invest and they add up to just buying a new saw. This saw was just more of a project to learn how a 2 stroke works and how the engine is constructed and just basically practicing on it. But since I was at it, I was eager to give it a shot and bring it back from the dead and see if she will run again.

And no, I did not do a Pressure / Vac test since I don't have the equipment for it. But since you metioned it, I think it does have some kind of air leak somewhere.

Everytime I'm done pulling the starter rope, I hear this fusssssss sound as if air is leaking somewhere.

 

[dswensen]

Well as said before, here are the pictures:

Carburetor Pictures:

Hard for me to tell, but in the picture of the "new" carb mounting face (picture 4), it appears as though the impulse opening in the mounting face of the carb is closed off.

Is it?

 

[PANDEMICBANDIT]

Hard for me to tell, but in the picture of the "new" carb mounting face (picture 4), it appears as though the impulse opening in the mounting face of the carb is closed off.

Is it?

Are you talking about the two holes (one on left and one on right) where the mounting studs go?

Or is it the 3rd hole on the right side thats connected to that lever that moves at the same time as the throttle linkage moves?

 

[PANDEMICBANDIT]

One other question, there is no gasket maker between the crankcase and cylinder. Can that be another reason that its leaking air?

And I also noticed that the saw is leaking small amounts of bar and chain oil.

 

[dswensen]

Are you talking about the two holes (one on left and one on right) where the mounting studs go?

Or is it the 3rd hole on the right side thats connected to that lever that moves at the same time as the throttle linkage moves?

No, the impulse holes would be the top and bottom, 90 degrees of rotation from the mounting stud holes. Impulse air comes from the crankcase and drives the fuel pump diaphragm up and down to pump fuel. Some saws have a separate hose for this (my Stihls do), and others, like the Poulan and Poulan variants are "face feeders" - they draw their impulse air from the crankcase through holes in the mounting face of the carb.

I assume yours is a "face feeder" too. Both of those holes in the face 90 degrees of rotation from the mounting studs will not be open, but one of them has to have a passage that leads into the chamber where the fuel pump diaphragm lives.

Again, from the picture, it appears that both of those holes are blocked off on your carb, but it's hard to tell. Wouldn't be the first time that an AM carb didn't have the impulse hole drilled properly.

 

[PANDEMICBANDIT]

No, the impulse holes would be the top and bottom, 90 degrees of rotation from the mounting stud holes. Impulse air comes from the crankcase and drives the fuel pump diaphragm up and down to pump fuel. Some saws have a separate hose for this (my Stihls do), and others, like the Poulan and Poulan variants are "face feeders" - they draw their impulse air from the crankcase through holes in the mounting face of the carb.

I assume yours is a "face feeder too. Both of those holes in the face 90 degrees of rotation from the mounting studs will not be open, but one of them has to have a passage that leads into the chamber where the fuel pump diaphragm lives.

Again, from the picture, it appears that both of those holes are blocked off on your carb, but it's hard to tell. Wouldn't be the first time that an AM carb didn't have the impulse hole drilled properly.

Yeah sorry if I did not know what they were right off the bat, I'm still getting used to these type of carbs, but I really apprecitate it for explaining it to me. Now its starting to make more sense.

I looked at the pic a bit more carfully and the impulse holes are blocked on the new carb.

 

[dswensen]

Yeah sorry if I did not know what they were right off the bat, I'm still getting used to these type of carbs, but I really apprecitate it for explaining it to me. Now its starting to make more sense.

I looked at the pic a bit more carfully and the impulse holes are blocked on the new carb.

OK, well, if that's true, that might be your issue. Again, there has to be some way for the impulse air from the crankcase to get to the fuel pump side of the carb. If there isn't a separate impulse line to connect to the carb from the crankcase, then there has to be another way (like face feeding). Maybe find the hole where carb mates to the saw that would match the location of one of the holes in the carb we have been discussing. With the plug removed form the saw, pull the saw over with the starter while holding your finger over the hole on the saw-side mating surface and see if you can feel the impulse air. If you can feel it, that is where the hole in the carb side of the mating surface must line up to transfer that impulse of air from the crankcase to the carb, assuming that hole is open to create a passageway to the innards of the carb.

 

[PANDEMICBANDIT]

OK, well, if that's true, that might be your issue. Again, there has to be some way for the impulse air from the crankcase to get to the fuel pump side of the carb. If there isn't a separate impulse line to connect to the carb from the crankcase, then there has to be another way (like face feeding). Maybe find the hole where carb mates to the saw that would match the location of one of the holes in the carb we have been discussing. With the plug removed form the saw, pull the saw over with the starter while holding your finger over the hole on the saw-side mating surface and see if you can feel the impulse air. If you can feel it, that is where the hole in the carb side of the mating surface must line up to transfer that impulse of air from the crankcase to the carb, assuming that hole is open to create a passageway to the innards of the carb.

I did remove the spark plug and placed my finger over the hole, and I actually feel alot of air when the starter rope is pulled. I'm assuming thats a good thing. But I really don't think its a carb problem. When I let go of the starter rope, I hear a fuss sound as if air is escaping somewhere. It sounds like its coming from either the flywheel or the crankcase because when I took it apart to inspect the engine I did not put any gasket maker between the crankcase and cylinder to prevent any leaks. So I think thats the problem.

 

[dswensen]

I did remove the spark plug and placed my finger over the hole, and I actually feel alot of air when the starter rope is pulled. I'm assuming thats a good thing. But I really don't think its a carb problem. When I let go of the starter rope, I hear a fuss sound as if air is escaping somewhere. It sounds like its coming from either the flywheel or the crankcase because when I took it apart to inspect the engine I did not put any gasket maker between the crankcase and cylinder to prevent any leaks. So I think thats the problem.

Yep. If you have an air leak large enough that you can hear it, that is definitely a problem. Good luck with your project. As others have said, dollar-wise, this is not worth your time, but as an education, it's invaluable.

 

[J.W Younger]

I did remove the spark plug and placed my finger over the hole, and I actually feel alot of air when the starter rope is pulled. I'm assuming thats a good thing. But I really don't think its a carb problem. When I let go of the starter rope, I hear a fuss sound as if air is escaping somewhere. It sounds like its coming from either the flywheel or the crankcase because when I took it apart to inspect the engine I did not put any gasket maker between the crankcase and cylinder to prevent any leaks. So I think thats the problem.

The ultra gray silicone is what I use.
Also on that little saw the crank seals are serviced with the bearings.

 

[PANDEMICBANDIT]

Yep. If you have an air leak large enough that you can hear it, that is definitely a problem. Good luck with your project. As others have said, dollar-wise, this is not worth your time, but as an education, it's invaluable.

Yeah thats what this saw was mostly for from the start was just a learning project. I just invested a few bucks here and there to see if it will start. But I did not want to invest whole lot of money and time into it and their still probem after problem. But as you said, as an educational purpose to learn from it, its worth it.

So I just want to say Thanks to everyone for your help, I really appreciate all the advice and techniques. But as dwensen as said, its just not worth investing so much time into it. But it was one hell of a learning experience. So I've decided to just keep this bad boy for parts mainly because the engine is in really good condition. Maybe I'll get lucky and come across another saw either the same or identical and I can swap out certian parts.

One last question,

So as I metioned before in previous posts that I put in a new carb. I'm going to just keep that carb as a spare in either a small container or a small box.

But does anyone know the process of how I would drain out the fresh fuel from the carb. It is brand new and its only been in the saw for maybe a couple of days now.

Do I just use some carb cleaner and give it a good spray and then let it dry for a few hours and its ready for storage or?......

I perfer not to dissamble the new carb fearing that anything I put back together wrong and the carb does not function correctly. But then again I don't want to leave any fresh fuel in the carb while its being stored until I need it again and find that its all gummed up which leads to more headaches.

If I need to diassemble it to clean it through so that I don't have to worry about it being gummed up while its being stored, then I'll go ahead and do that if their really isn't another option.

Any ideas?

 

[a. palmer jr.]

One possibility. It was said in this thread that the impulse ports did not match up between the engine and the carb so it's possible no fuel ever got into the carb. Probably just spray off the outside of the carb if indeed this is the case.

 

[TBS]

I did remove the spark plug and placed my finger over the hole, and I actually feel alot of air when the starter rope is pulled. I'm assuming thats a good thing. But I really don't think its a carb problem. When I let go of the starter rope, I hear a fuss sound as if air is escaping somewhere. It sounds like its coming from either the flywheel or the crankcase because when I took it apart to inspect the engine I did not put any gasket maker between the crankcase and cylinder to prevent any leaks. So I think thats the problem.

If the crankcase leak is large enough it won't generate an impulse to pump fuel.
Get some ultra copper gasket maker and get it going.

 

[PANDEMICBANDIT]

But as metioned in my previous post, how should I clean out my new carb of fresh fuel to get it ready for storage?

 

[dswensen]

But as metioned in my previous post, how should I clean out my new carb of fresh fuel to get it ready for storage?

Loosen the cover screws on both sides and let it drain? If you are worried about taking the covers all the way off, don't do that - just loosen the covers.

 

[PANDEMICBANDIT]

Loosen the cover screws on both sides and let it drain? If you are worried about taking the covers all the way off, don't do that - just loosen the covers.

That's actually a really good idea. Thanks for the advice, I really appreciate it. And if you don't mind me asking, can I let it drain for a few hours and its good to go? Or is leting it dry take longer than that?