Help--trying to get a Husky L65 to run

[olyeller]

I'm starting a new post since I now have a new-to-me, old Husqvarna L65 identified, cleaned up and starting to run. Thanks for the help you guys gave me on the earlier thread. Here are the pertinent details from my other post:

I got the L65 running! It will start cold, then run for one or two minutes, won't idle so I keep feeding it throttle, then it cuts out. I pulled the plug and it has spark, but won't start warm. Compression feels good. I just tried starting it again after 30-60 minutes and it fired up cold, runs for one or two minutes, then stops, same as before.

What do you think this might be? Does this model have an impulse line that might be leaking air? Fuel line looks good and soft, no gas leaking out. This is my first try at trouble-shooting, and now I'm stumped! This could be a good runner if I just solve this issue.

Later:
Worked on it some more and I think it's the impulse line. On the left side under the air filter cover there's a little aluminum spigot coming up out of the fuel tank that looks like it should take a line of some sort; is that just the breather for the fuel tank? Also, there’s an open hole in the Tillotson carb right next to the adjustment screws. Is this where the impulse line should go? Does the impulse line draw pressure off the cylinder somewhere?


As I said,I am new to troubleshooting saws, and I did a search on impulse lines already. Any help is appreciated. And sorry, my camera is not at home, so no pics right now; I'll get some up tomorrow.

olyeller

 

[PES+]

Where's fish?

I'm starting a new post since I now have a new-to-me, old Husqvarna L65 identified, cleaned up and starting to run. Thanks for the help you guys gave me on the earlier thread. Here are the pertinent details from my other post:

I got the L65 running! It will start cold, then run for one or two minutes, won't idle so I keep feeding it throttle, then it cuts out. I pulled the plug and it has spark, but won't start warm. Compression feels good. I just tried starting it again after 30-60 minutes and it fired up cold, runs for one or two minutes, then stops, same as before.

What do you think this might be? Does this model have an impulse line that might be leaking air? Fuel line looks good and soft, no gas leaking out. This is my first try at trouble-shooting, and now I'm stumped! This could be a good runner if I just solve this issue.


This is new......"message too short"

now we need to write books here to post?
Later:
Worked on it some more and I think it's the impulse line. On the left side under the air filter cover there's a little aluminum spigot coming up out of the fuel tank that looks like it should take a line of some sort; is that just the breather for the fuel tank? Also, there’s an open hole in the Tillotson carb right next to the adjustment screws. Is this where the impulse line should go? Does the impulse line draw pressure off the cylinder somewhere?


As I said,I am new to troubleshooting saws, and I did a search on impulse lines already. Any help is appreciated. And sorry, my camera is not at home, so no pics right now; I'll get some up tomorrow.

olyeller

The impulse is fed through the carb block from the cylinder to the face of the carb.....check the gasket and block passage for clogs but I doubt that is the problem.

You likely need ignition work.....points and condenser or a spark module to take the place of them.

 

[Lust4saws]

The "spigot" you're referring to is actually the tank vent. There is supposed to be a piece of tubing on it which is routed to the right side of the saw. It's purpose is to relieve excessive tank pressure, but often times (especially in hot conditions) it would not work properly and cause vapor lock.
What I have done, is unscrew the valve and using a small punch, drive out the roll pin, then remove the check ball. Throw the ball away. Then replace the roll pin, reinstall the vent and it's tube. You'll have to install a piece of cotton in the tube to keep gas from pouring out (it had a piece in there originally too).
That saw doesn't have an impulse line.
Dave

 

[HiOctane]

Hmm,looks like an ignition problem.You gonna need a module but i doubt they are still available.

 

[Lust4saws]

The 65 has points--not electronic ignition.

 

[olyeller]

Thanks for the input, guys. I read on Acres site that this is a points saw, and I had spark after the engine cut out--so I don't think it's an ignition issue. I was wondering where the impulse line would go, so I'm glad to learn it doesn't have one! When I get home tonight I'll do a quick check on the tank vent by just removing it to see if it keeps feeding fuel. Thanks for the tip Lust4saws. Also, I did check the fuel filter on the fuel line in the tank and it looked relatively new, no clogging or decomposition so that's not the problem.

On a side note, why does this design not use/need an impulse line? How does fuel keep flowing to the carb when the fuel level sits below the carb? I can't figure that one out.

 

[HiOctane]

On a side note, why does this design not use/need an impulse line? How does fuel keep flowing to the carb when the fuel level sits below the carb? I can't figure that one out.

i guess external impulse line is used when space for the hole in cyl or flange is not available due to design of cyl.intake.With no pulse line,there is an hole from the cyl going tru flange to a small hole in the carb connected to the pump diap.So when the piston moves up and down,a vacuum and pressure is built up inside the carb that makes the pump diap moves up and down sucking gas from the tank.

 

[olyeller]

i guess external impulse line is used when space for the hole in cyl or flange is not available due to design of cyl.intake.With no pulse line,there is an hole from the cyl going tru flange to a small hole in the carb connected to the pump diap.So when the piston moves up and down,a vacuum and pressure is built up inside the carb that makes the pump diap moves up and down sucking gas from the tank.

Thanks for that info, HiOctane. Just for curiosity's sake, I guess I'll have to take this carb off and take it apart to see what this is all about. I've worked on motorcycles for years, but these small engines have a few twists; I always try to avoid inverted riding whenever I can, so a float-bowl carb is just fine with me!

 

[HiOctane]

Thanks for that info, HiOctane. Just for curiosity's sake, I guess I'll have to take this carb off and take it apart to see what this is all about. I've worked on motorcycles for years, but these small engines have a few twists; I always try to avoid inverted riding whenever I can, so a float-bowl carb is just fine with me!

Remove the carb.Look at the back of carb,you gonna see a small round hole,less than 1/8".Remove the the cover holding the the pump diap,the one with 2 small"tongues" on it.You will the hole passage coming from the back of carb.
Look here.http://www.tillotson-fuelsystems.com/manuals.html
Choose the HS model .

 

[olyeller]

Still stumped

That's a great link to the Tillotson info HiOctane--thanks so much.

I couldn't post last night while AS was down, but as previously suggested I checked the aluminum vent tube and--no roll pin, no little ball for a check valve, just a straight shot up for venting. Therefore, no chance for vapor lock, and the saw wasn't getting hot enough for that anyhow, now that I think about it.

So now I'm guessing there's either a blockage in the passageway between the cylinder and the carb where pressure feeds through in place of an impulse line, or maybe there's something wrong with the carb and it needs to be rebuilt? Any other ideas?

And here are some photos of this oldie Husky, as promised. It's in pretty good shape overall; I just want to get it running and see how she cuts!

 

[vintagestuff]

Bad crank seals? (Sealing when cold and expanding and not sealing when hot?) I have a homelite c-7 that has same symptoms. It has good compression, spark, and someone rebuilt carb and replaced fuel line before I acquired it.