Boiling fuel

[Marc1]

I was given a few 18" logs of very dry eucaliptus and chopped it up with my litle XL. All was good but after pushing the little beast through this bone dry extra hard stuff for a while. power started to fade, so I stopped it and noticed that the petrol was boiling. I let it cool down, cleaned the air filter, released the pressure from the tank and got it going again for another half hour and again it faded.
I have not used it since but I wonder if I have done some damage. Is this boiling the fuel a comon thing? I remember my old Mculloch 200 use to do it. The chain was reasonably sharp, I mean reasonably, you cannot expect to get big chips out of dry tallowood.

 

[bama]

If you released pressure from the tank, it could be a plugged tank vent.

 

[spike60]

I apologize for asking a question this stupid, but I saw a customer do this once on a tractor. Did you shut it off before you checked it? That customer checked his fuel when the tractor was still running and is was the vibrations rippling in the fuel that caused hime to think it was boiling.

 

[PES+]

A classic overheat...vaporlock

That is not at all uncommon in fairly high heat and or heavy load use particulalry with a metal fuel tank. It usually is not fatal unless you repeatadly run the saw to stalling and if repeated long enough will cause a seizure. I have even had older metal tank huskys do it 266 268 etc. The Stihls never did for me due to the tank and carb being seperated from the engine.

 

[PES+]

By the way

By the way a proper tank vent lets air IN but not OUT. the XLs used a duck bill vent if you are talking Homelight XL

 

[WRW]

That is not at all uncommon in fairly high heat and or heavy load use particulalry with a metal fuel tank. It usually is not fatal unless you repeatadly run the saw to stalling and if repeated long enough will cause a seizure. I have even had older metal tank huskys do it 266 268 etc. The Stihls never did for me due to the tank and carb being seperated from the engine.

I had that happen with a Stihl, but it seemed to be more fuel/grade related.

 

[PES+]

Really?

Really?
Just curious which model and how hot was it?
I could see it happen running winter gas in the summer as they add extra volatiles in the winter gas blend

 

[WRW]

It was an 041. Temps were upper 80's. Using 87 octane BP. Changed brands and the problem went away...at that time the recommended octane was 87.

 

[blis]

happens around here sometimes in hot summer days when limbing alot... shouldnt be dangerous if you shut down the saw and let it cool down for while when gas starts boiling...

 

[ShoerFast]

Marc1

To understand what is happening, think of petrol , or gasoline as a mixture of Butane and grease, it really is more simple then that, however there are lighter and heaver particles in gasoline that turn to a thick varnish when the vapors "boil" of evaporate off.

Gasoline is given a few labeling caricaturistes to rate how they will run, one of the most simple labels is it's RVP , or "Read Vapor Pressure" rating. To get the RVP you simply need to cap a sample with a PSIG pressure gauge and take the pressure reading at 150 deg. F, higher numbers improve cold starting while lower numbers are better preventing vapor-locking and hot stalling. Switching brands, grades, or the time of year you buy your fuel will change this rating.

What you are seeing are the lighter molecules bubbling off, one of the best ideas of modren saws was to separate the fuel tank into the handle so the engines heat wouldent effect the supply.

 

[Hard Knocks]

I also had an XL Homelite and a Pioneer with attached metal tanks that did the same thing. On a warm day you could count on the fuel boiling. It never caused any problems with the saws.

 

[ghitch75]

boiling fuel in an XL is a scorded piston problem...had one.. only after a new piston and rings and then it would cut in 90 degree with out boiling the fuel

 

[SteveH]

Not familiar with your saw, but I had an Echo back in the seventies, don't recall which model, that used to boil sometimes. When I bought it, the dealer told me that one nice feature of the saw, which was my first and I knew nothing, was that the gas in the tank helped cool the engine.... It didn't have a separate gas tank sitting on the side like my Stihls do. Now and then, with heavy use, the gas would boil and I'd have to let everything cool down a while. Only time I opened the filler cap, fuel boiled out all over and luckily didn't ignite.

 

[RaisedByWolves]

boiling fuel in an XL is a scorded piston problem...had one.. only after a new piston and rings and then it would cut in 90 degree with out boiling the fuel

HUH???



Most likely the scored piston was caused by the saws cooling fins being clogged, the same thing that was causing the fuel to boil over.


Marc1

I think your talking of a SXL, the lil xl's had plastic tanks and arent likely to do this.



Remove the pullstart and clean out the cooling fins of all buildup. Then remove the flywheel and clean out the air gap between the crancase and the fuel tank.

This air gap is here specifically to keep the engines heat from being transfered to the fuel.




That will solve it!

 

[ghitch75]

HUH???



Most likely the scored piston was caused by the saws cooling fins being clogged, the same thing that was causing the fuel to boil over.



I think your talking of a SXL, the lil xl's had plastic tanks and arent likely to do this.



Remove the pullstart and clean out the cooling fins of all buildup. Then remove the flywheel and clean out the air gap between the crancase and the fuel tank.

This air gap is here specifically to keep the engines heat from being transfered to the fuel.




That will solve it!

and yes it was a SUPER XL with metal fuel tank...that is what fixed mine it never has boiled fuel after that...btw all my saws are all ways stripped and cleaned after every cutting....never mind thought it ment xl-12

 

[RaisedByWolves]

Glitch, I had to modify my post for clarity.



Your XL-12 is allmost a clone of the SXL.

 

[PES+]

XL and Homelite

I may have it wrong but I remember the XL being all metal with metal tank the plastic started with XL-2 and super 2 IF I had a dime for every model Homelite with XL in it I'd be retired or Vice President:jester:

 

[PES+]

Yup

The plastics were super XL and XL2

The original XL was all metal from 1965
had a few
Got a pic somewhere

 

[PES+]

Homelite XL ad

Ad for XL

 

[RaisedByWolves]