562xp Hot start?

[weimedog]

I believe the primer can't pump fuel, because the fuel in the carb or fuel in the lines has turned to a gas, at this point I believe the primer will no longer function. I shut the saw off to move some logs around, the tank sight prevents you from running out of fuel as long as you check on it every few minutes. Also this has happened a few times now, even with pretty much a full tank.

Even so I would expect the primer to be able to pull it through...it does when you start with an empty system and then put in fuel...prime to start. It starts with straight air and can pull the fuel. How hot would that carb have to get to vaporize gasoline instantly and continuously to the point it overcomes an active "pump" like the primer? I remember those old Homelites that would boil the gas in their tanks! A disconcerting feeling to say the least! There is the rubber intake that keeps the carb from getting heat through conduction from the cylinder. And that "dam" would keep the hot air from coming through. Where is the heat coming from? Does the autotune system add heat to the carb? Or is it just sensitive regardless. Wonder what the temps under that cover are. I would expect the air flow from the flywheel side to help. Unless the flywheel itself is hot. And yet again the location of all those clips & autotune stuff on the flywheel side of the carb might be blocking the cooler air. Or insulating the heat in....Questions....questions.

I'm going to try and replicate that condition this weekend, and poke a laser thermometer around .. if its hot enough. I'm going under the assumption if I run it really hard and then just kill it, my first clue will be the primer bulb being empty and not being able to draw fuel. Is that correct?

Also..what is the possibility of it being a tank venting issue? Wonder if releasing the cap shows any signs of pressure in the wrong direction. Maybe heat makes the vent fail?

 

[quotedraven]

I had this problem on one day only. It apparently fixed itself. It was it the dealer for a while and he could not replicate the issue. I was cutting very hard wood probably dirty and my chain was likely not sharp enough. Still I could see if you were a pro that this could be a big problem but hey a pro would have multiple backups right?

 

[skylogger]

Where does the 550 and 562 draw air from for the carburetor?

 

[quotedraven]

Where does the 550 and 562 draw air from for the carburetor?

The filter

 

[skylogger]

The filter

Lol, I meant where does outside air enter the air box. When the top cover is on it looks sealed other than the cracks where the cover meets the saw.

 

[reedo]

I have a 550xp that would not oil when new. Turns out the tube the oil traveled through was a defective part and had no channel. Is there any way it may have a defective part somewhere? Just a thought.

 

[drumbum]

I would try to bypass the primer bulb as a test.

 

[blsnelling]

I would try to bypass the primer bulb as a test.

And mod the muffler. The saw should run cooler.

 

[Chris-PA]

Even so I would expect the primer to be able to pull it through...it does when you start with an empty system and then put in fuel...prime to start. It starts with straight air and can pull the fuel. How hot would that carb have to get to vaporize gasoline instantly and continuously to the point it overcomes an active "pump" like the primer?

The fuel is at or above its boiling point, and just like with steam when it changes state the volume increases drastically. In fact when you reduce the pressure on a liquid the boiling temperature drops, and that is just how the purge bulb works, by creating a lower pressure at the end of the line.

So basically you just keep pulling vapor out of whatever liquid fuel is there, and it can supply plenty, so you never pull any liquid fuel.

I've read that gasoline can boil as low as 90F, depending on if it is winter blend and/or is E10. I doubt it's that low in most cases, but reduce the pressure over it and there is very little margin.

 

[JDschenk]

I got a husqvarna 562xp we use at work commercially. And we had starting issues as well, and now this summer when it turns 90 or very humid out. It leaks out so much gas it soaks the air filter. Took it to the dealer and they can't find the leak. Only leaks like that laying on clutch side.

 

[MountainHigh]

any used 562 mufflers around? Want to gut my muffler but don't want to lose my extended warranty just yet.

 

[sunfish]

any used 562 mufflers around? Want to gut my muffler but don't want to lose my extended warranty just yet.

I bought a new one from spike60 a couple years ago. Don't remember the price, but was surprised how cheap it was.

 

[albert]

If the carb or anything before the pump (carb) is hotter than the fuels boiling/vaporization point the primer and the carb can't pull fuel no matter what until parts and fuel cool below that temperature. Not always possible, leave the saw run and don't shut it off to refuel is an option. Not something you should have to do, but is one way to get by and not feel like throwing the saw like Ted Knight threw the golf club in caddy shack.

 

[weimedog]

The fuel is at or above its boiling point, and just like with steam when it changes state the volume increases drastically. In fact when you reduce the pressure on a liquid the boiling temperature drops, and that is just how the purge bulb works, by creating a lower pressure at the end of the line.

So basically you just keep pulling vapor out of whatever liquid fuel is there, and it can supply plenty, so you never pull any liquid fuel.

I've read that gasoline can boil as low as 90F, depending on if it is winter blend and/or is E10. I doubt it's that low in most cases, but reduce the pressure over it and there is very little margin.

I see..

 

[CoreyB]

Could carry some dry ice and put a little piece next to the carb when you shut it off. See if that works.

 

[damifino]

Could carry some dry ice and put a little piece next to the carb when you shut it off. See if that works.

Like I said, I have seen a good response from others with good concern and information about this issue and then there are some that just sound stupid.

 

[Termite]

The fuel is at or above its boiling point, and just like with steam when it changes state the volume increases drastically. In fact when you reduce the pressure on a liquid the boiling temperature drops, and that is just how the purge bulb works, by creating a lower pressure at the end of the line.

So basically you just keep pulling vapor out of whatever liquid fuel is there, and it can supply plenty, so you never pull any liquid fuel.

I've read that gasoline can boil as low as 90F, depending on if it is winter blend and/or is E10. I doubt it's that low in most cases, but reduce the pressure over it and there is very little margin.

Chris, do you know the boiling temperature of AVgas?
I found ExonMobil boiling 170 degrees C max = 338 F.

 

[CoreyB]

Like I said, I have seen a good response from others with good concern and information about this issue and then there are some that just sound stupid.

None as stupid as leaving a problem for years of production and ignoring the small percentage of customers that have the problems. I am sure more then a few dealers have had some unhappy customers that they can't help.
I guess my thought was if you could get the temp down and would allow a guy to get back to work instead of standing around waiting for it to cool down.
I guess that is stupid.

 

[Termite]

I just read the most thorough and concise write up about av gas. This was a good read for me.
Maybe the fuel is the solution?
http://www.race-dezert.com/forum/threads/100ll-avgas-ok-to-run.44599/

 

[CR888]

Reflective heat shield tape directing heat AWAY from carb should help a lot. This is not a AT or fuel related issue folks.