Help w/ a Husky 450 X-Torq

mark617

mark617

New Member
Joined
Mar 19, 2020
Messages
1
Location
earth
First off hello. I have utilized the information here to get me this far. Thank you for that. I am stuck now, though.

I am working on a Husqvarna 450 X-Torq. It's my parents and it was neglected. So far I have downloaded the service manual. I have replaced the spark plug (gap set at 0.5 as per manual). I am using the Husqvarna 2 stroke oil at a 1:50 ratio with 87 octane. I have replaced the air filter and the carb (idle screw portion was broken). All the fuel lines are fine and the filter is new. One odd thing though, when I fill it with gas a little comes out. I thought it was the lines, but it is not. So, it must be the vent plug. I am not sure this is normal / safe. I can't imagine that should happen, but it seems a common thing when I search online. People with the issue just say fill it up fast, which I do. And, outside of a few drops, it's fairly dry near the vent. I have only adjusted the carb settings to a very basic point. The machine will idle, though it's a bit rough, but it stays on. Idle RPMs range from about 2400-2900 via my Tiny Tac. Manual says [email protected], but it ran better at around 3000 on the last carb. The new carb is the OEM Zama.

After letting the saw get warm, I find when I give it some gas, it bogs down a little at the start / lower RPMs. I take this to be an issue with the L adjustment. I can adjust the carb via the spline tool, but I simply don't have the skill / ear to get it tuned perfectly. I know to err on the rich side.

The big problem though is that after about 10 minutes of cutting, the saw will shut off. It will usually start with the high idle a time or two, but eventually it will not start at all. Also, sometimes when I start it after it is warm, the chain starts moving at cutting speed (very dangerous). Come the next day, it starts easily enough cold (usually without the choke). This says to me maybe it's set too rich at the low end, because I do not think it should start right up (perhaps this is because I am so used to the thing being out of tune / worn that I fail to recognize correct function). I do not think it is vapor locked, but honestly I don't even know how to tell. I read if you open the gas tank and it gives off a hiss, that is a sign. I fail to get any sort of hiss if I open the tank.

So, what's the next move(s)? I do not have any advanced tools (or skill, really) to tackle the advanced stuff. Am I at a point where I need to take it to an expert? I would prefer not to, as I really enjoy the process / learning. And, if I destroy the saw, hell, I can just buy a new one. The education alone is worth $350 (to me).

Thank you for your time.
 
Huskitoter

Huskitoter

ArboristSite Operative
Joined
Jan 17, 2018
Messages
456
Location
Georgia
Don't be too quick to dismiss the fuel line. They get soft and gummy right inside the tank. It may be the source of your bog and leak. Have a gander at this video where an experienced tech doesn't catch it when working on the carb. youtube.com/watch?v=B-v6dlk2bo4

Cutting off when hot could be from loss of compression. Best thing to do is remove the muffler and inspect the piston and rings for scoring. Post a pic of the ring to get started.
 
Top