MountainHigh
Selective Tree whacker
I'm taking mine in to the shop today and will post here when I get some news.
562xp warm start trouble, air purge stops working for a while
- Thread starter Solrael
- Start date
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Am I the only one who lets a saw cool down before shutting it off? I'm not suggesting that will solve your problems but I just noticed it sounds like you just shut her down after the cut.
I interested in what the dealer will come up with. I don't own one those saws but most of the guys change out the carb to the new one. Also have you down a leak down test?
Sent using mental telepathy.
I interested in what the dealer will come up with. I don't own one those saws but most of the guys change out the carb to the new one. Also have you down a leak down test?
Sent using mental telepathy.
MountainHigh
Selective Tree whacker
I have tried both shutting down directly after using it hard, as well as letting it idle for a couple minutes before shutting it down. When it gets to a certain stage, either way, it still won't re-start.
Haven't done an air leak test yet, but it's on my list for the dealer ;-)
Nice thing about a warranty, somebody else does the work.
Bad thing about a warranty, somebody else does the work.
Actually I am lucky. I have a dealer 30 minutes from me who is very competent and knowledgeable.
Sent using mental telepathy.
Bad thing about a warranty, somebody else does the work.
Actually I am lucky. I have a dealer 30 minutes from me who is very competent and knowledgeable.
Sent using mental telepathy.
albert
Addicted to ArboristSite
Why does it seem like this series of saws transfer more heat to the fuel tank than most other saws that have a seperate plastic tank? Seems to be the cause of this trouble. Winter blended fuel used when temperatures moderate will add to the problem. Idling for a short time before shutting off does not seem to help much. The operator should not have to do much else.
You just asked a question about thermodynamics. Bring the engineers in please. Lol
Cycledude
ArboristSite Operative
My saw does it in both warm and cold weather , I could be wrong but outside temperature doesn't seem to have any effect, the saw is a year old and it's only done it when shut off after hard cutting but it's been a issue since brandnew, I believe chainsaw wizzard's answer about needing a couple of updated parts will fix my saw issues but I'm curious to hear what happens with MountainHighs saw before I take mine back again, my dealer place has only been selling chainsaws for a few years but they have always treated me good so I got no complaints with them.
albert
Addicted to ArboristSite
Fuel bubbling in the tank, purge/primer bulb air bound, not being able to move fuel ect. All seems to be due to tank absorbing too much heat. Fuel type and blend can add to this. I do not know first hand of any other fairly contemporary saw that have this trouble. I don't think a coil or carb update can address this particular problem.
Pud
ArboristSite Operative
Ive been through all the same crap with mine and theres no fix they just run too hot , dunno if its from been strato , the angled back head been to close to the carb , massive muffler acting as a heat soak or the engine cover been to tight around the cylinder to allow good airflow or all of the above but they just get vapor lock and refuse to go.
Cycledude
ArboristSite Operative
I know the oil tank gets very hot and maybe the gas tank does also but I've never noticed it, maybe next time I'm having this trouble I will stick finger in tank to see how hot it is.
Mine wouldn't start a couple times a few weeks ago when it was warm outside. I cut with it for one tank. Then after refuelling it would not start back up. I eventually got it to start with the choke on. Purge bubble was empty and would not pull fuel. This is a saw that was replaced under warranty due to a leaking decomp that scored the cylinder. . This is a 2015 model. I got this new saw in the winter. It never had any trouble starting until the weather warmed up a bit...
Topbuilder
Mouth breathers need not apply.
Everyone is saying the fuel in their tank is boiling... somewhere around 175 F. You are going to check that out with your finger...
Cycledude
ArboristSite Operative
Yes will be checking Very carefully.
Others say the purge doesn't work, that's one thing I've never noticed with my saw.
Chris-PA
Where the Wild Things Are
My experiences with vapor lock probably don't compare exactly, as I'm running E10 in cheap homeowner saws. Usually I don't have much trouble with it at temperatures in the 70's, except sometimes early in the year when winter blend fuel is still in the system.
I've had issues with my plastic chassis Poulans where the fuel tank is part of the plastic case, and also with my small chassis Zenoah designs (G3800, GZ400/4000) with a split case and fuel tank in the plastic handle. I've tried to figure out where the fuel is heating, and I don't think it's in the tank on my saws - if it were I could not get them going again. It seems to be in the carb itself. While running the carb is cooled by the continuous air flow and vaporizing fuel. If I shut it off for a short time it's OK, but if off long enough the carb gets too hot. Then it can't pump fuel, and when the purge bulb tries to pull fuel through it the fuel boils.
But if I use full choke on some saws it can eventually start. I've had hots saws on 95+deg days sit and run on full choke for quite a while, until enough air flows through the carb to cool it back down. And then it runs perfectly normally again, for as long as I need it to, until I have to shut it down again.
When I first encountered these problems I was bringing saws back down to the barn and tearing fuel systems apart to find out what was wrong. There was never anything found, and I'd put them back together just as they'd been and they'd fire right up like nothing had happened.
I've never seen a 562 though, so maybe there is something about the design that makes it more problematic - maybe they just run hotter, or maybe the fuel is already at an elevated temp sitting in the mag case with the engine (if that's how they're built). Maybe Huqvarna was working with the guys that designed the F35?
I've had issues with my plastic chassis Poulans where the fuel tank is part of the plastic case, and also with my small chassis Zenoah designs (G3800, GZ400/4000) with a split case and fuel tank in the plastic handle. I've tried to figure out where the fuel is heating, and I don't think it's in the tank on my saws - if it were I could not get them going again. It seems to be in the carb itself. While running the carb is cooled by the continuous air flow and vaporizing fuel. If I shut it off for a short time it's OK, but if off long enough the carb gets too hot. Then it can't pump fuel, and when the purge bulb tries to pull fuel through it the fuel boils.
But if I use full choke on some saws it can eventually start. I've had hots saws on 95+deg days sit and run on full choke for quite a while, until enough air flows through the carb to cool it back down. And then it runs perfectly normally again, for as long as I need it to, until I have to shut it down again.
When I first encountered these problems I was bringing saws back down to the barn and tearing fuel systems apart to find out what was wrong. There was never anything found, and I'd put them back together just as they'd been and they'd fire right up like nothing had happened.
I've never seen a 562 though, so maybe there is something about the design that makes it more problematic - maybe they just run hotter, or maybe the fuel is already at an elevated temp sitting in the mag case with the engine (if that's how they're built). Maybe Huqvarna was working with the guys that designed the F35?
Chris-PA
Where the Wild Things Are
But is there any sign that the engines are overheating while running? I think it's important to make the distinction between the fuel system getting too hot to work during heat soak after the engine (and cooling) stops, and the engines overheating while running.
Also, a strato pulls fresh air across channels in the piston wall and down the transfers every revolution, which does not happen in non-strato engines. So while it may have some 20% less fuel going through (and associated evaporative cooling), it is somewhat offset by the additional fresh air charge.
MountainHigh
Selective Tree whacker
562 is now in shop with lengthy description of issue attached to it. They said 2 days but I'm betting they take longer.
Very true, you can see the buildup on the piston which indicates drastic temperature changes do to the incoming cool strato air. I've found engines ran on the gagged edge often run into starting issue after setting a few minutes. A simply look at the exhaust side of the piston would clue us in on how truly far these saws are pushed.
The newest 562's no longer have the tank vent hose in the carb box, maybe the vacuum was sucking in warm air?
Pud
ArboristSite Operative
Plug it into the computer and look at the carb temps ... The carbs get hotter than the boiling point of fuel
Chris-PA
Where the Wild Things Are
What data does it give you? Just a max temp?
Anyway, if it shows temps at the carb of that value, then there is the evidence. A carb cannot pump vapor so it can't work at such temperatures. How could the carb get that hot while running with air flowing through it? Seems like those must be hot soak temps.
