JohnBoyy

Thread revival! I was busy with a million things in the spring so I just worked on with the stihl 180 and a little ego battery saw. we took down a dozen ash trees in the spring and there was loads of tops to be cleaning up with the small saws. I took the carb off and could see nothing wrong. these saws have a rubber inlet manifold which seemingly can also crack but it looked perfect so I got a rebuild kit and took the carb apart. I didnt 100% strip it out of fear of not getting it back together properly, didnt remove the jets/needles. I couldnt see anything glaringly obviously wrong, maybe the pump diaghpram was dodgy, or maybe I damaged it taking it apart. Eiether way I put it back together with a new fuel fiter and hose and with some fresh juice it fired right up. I've only done some relatively light work with it yet but it didnt seem to struggle or splutter at any point so I'm hopeful that I've done it right. I need to watch some more tuning videos on youtube to be sure I have the carb set right, last thing I want is to end up running lean. Thanks for all the advice folks.

Yeah there's definitely something bigger wrong, the breather is only highlighting the problem. It's also definitely getting worse on restarts. Have a pair of forceps on the way in the post, I don't fancy taking the carb off and not being able to get the fuel supply hose back on, it's a bit of an awkward spot under the carb. once that lands I'll dive into cleaning the carb and see how it goes.

Taking the fuel tank out is a total saw teardown, the fuel tank is the crankcase on this model saw. Crankcase for Husqvarna 455 Rancher Chainsaw - OEM No. 510 06 59-14 | L&S Engineers WWW.LSENGINEERS.CO.UK Crankcase for Husqvarna 455 Rancher Chainsaw Genuine Husqvarna Part. OEM No. 510 06 59-14 So I'll hold off on doing that for as long as possible! don't think it has a spark arrestor but I'll check, if it does it's not much good as she likes to blow sparks when cutting stacks of branches in the sawhorse. I'll get a carb kit, filter and hoses and do some more cleaning.

No joy I'm afraid. Once I got it into some sustained cutting at the weekend it started its usual tricks dieing a death on me. I swapped back in the spurious vent and no dieing issues, but I did have a few hot start problems then, which this saw never ever has, it's always unreal to start, max 3 pulls cold and always starts on the first pull when hot, so there's definitely something else up, also I felt on saturday that the purge bulb wasnt filling like it normally would That could be down to me taking the hoses on and off half a dozen times during the week too I guess. Fuel filter and hoses are probably a good idea, what else after that? strip and clean the carb? looks a more complex beast than carbs I've worked on before, but sure every day's a schoolday.

Took it for a test drive at lunch time. I don't have much big timber here but I ran it as hard as I could for 15 minutes. It spluttered once or twice but never died. if it was running 40% right before it was definitely 80-90% now. I'm now wondering did I manage to accidentally reinstall the blocked original breather rather than the new one the day I bought the new one to replace the leaky spurious one. Assuming saturday comes dry I'll be on the farm where I have a lot of ash down and I'll report back.

So now that I actually know what way the fuel flows I didn't like the fuel supply hose, it was twisted and a little kinked. I shot a bit of wd40 on the bush it passes through and pulled it up and down a bit and got it sitting happier. Cleaned the filter with carb cleaner even though it looked pretty spotless. Popped the plug which was what I thought was a fairly nice shade of beige. I've it all back together and will test tomorrow and report back.

I just realised the primer is on the return line, some dope!!!

Thanks for the tips folks. I've to check the fuel filter yet, but everything else looks good, fuel hoses look and feel good, no kinks or anything looking wrong. I've done some playing with the vacuum gauge, started by testing the three breathers I have. The original tank breather is clearly clogged, it holds about 3 inches of vacuum whereas the new genuine drops to zero in a second or two, so it definitely seems blocked the new spurious one barely registered on the gauge but that's no surprise since the metal element falls out. (so the first thing I'm wondering is there any chance I reinstalled the original genuine one, but I'm 99% sure I didnt) So I reinstalled the new genuine breather. I didn't remove the tank, It's not immediately obvious to me that you can on this saw, it looks to me to be part of the chassis. Then I pulled the fuel hose off the carb and pulled vacuum, and no fuel came through. I had 20 inches of vacuum for a few minutes, even with the tank open. currently fuel in the tank. If I swap and pull vacuum on the hose from the tank to the primer bulb inlet I can draw a hundred ml of fuel in a half dozen pumps. I'd have expected that I should be able to pull fuel through the primer as that's what the carb has to do to run? I came in to look at the parts diagram on the computer screen and it seems to plumbed right with the tank hose on top and carb on the bottom. https://www.hsqintec.sk/vykres/h460-mot.-pila.pdf page 22

To be honest I havent done anything specific because the leaky spurious breather left it running fine, One of the services the fuel line and filter were supposed to have been changed to no effect but I will check everything over again

I have a mityvac tester Mityvac MV8500 Pressure & Vacuum Tester Pump & Fittings EUROSMALLENGINEPARTS.IE Mity Vac Pressure & Vacuum Tester Pump & Accessories Checks Carbs, pipes & seals etc 2 in 1 tool for pressure & vacuum testing. what am I looking to see on the gauge?

Long time lurker, finally actually registered because I have a problem I can't figure out. I have a 460 rancher which dies under load once it's been running for a while, crack open the fuel tank and it will run fine for a few minutes then again, rinse and repeat over and over again. I replaced the fuel tank breather with a spurious one and it ran like a champ, but leaked fuel so I plumped for the genuine article and I was back to square one dieing out after a few minutes of any load. it seems I can have leaking fuel or crap running. Any thoughts as to what could cause this? Is there a fuel cap from a different model that might fit that would be vented, maybe two breathers might work? took it to two different saw shops who both could find nothing wrong (I suppose they cant so easy run under load on a workbench) I figured out the breathing issue myself, but I'm stumped as to where to go now. Any ideas wise people of arbtalk?