Hose out her GAP! Or, How to keep your Fuel cool.

[RBW]

Ok, so now that I have your attention Id like to talk about how to keep your fuel cool fool! Sorry, it just kind of rhymed...





In the past Ive heard people say...

"Gee willickers, I sure like those old Homelites, I just wish they wouldnt boil fuel all over my new dungarees mom just bought me. It makes me smell funny and I have a date toninght."



And I think, Sheesh, Give Homelite a break, They didnt design a new way to boil Gasoline, they designed a Chainsaw, and a darn good one! In fact, they made saws so good that they would run for Decades without so much as rudementary maintainence. And herein lies the problem, NEGLECT!




So, OK, What is an Air Gap?



Well, its just that, A 1/4" gap filled with air, in this case residing between two portions of the saw case, the HOT crankcase and Fuel tank. The function of the Air Gap is to keep the heat from the engine from migrating into the fuel tank and into the fuel.


The problem with neglecting this important design element of the saw is that when this area becomes packed with Dust, Saw dust, Oil and heat, it actually contains all the right elements to Conduct heat (Think Deep fryer) into the fuel.

The exact oppisite of what it was designed to do!!



Not only is a saw in this condition suffering the effects of neglect, its downright dangerous! Boilig fuel is VERY Flammable and all it would take would be an errant spark or a hot muffler to turn your Beloved saw into Minature Hiroshima in your hands.





So without further adeu, I will show you how to do some relativly minor maintainence that can pay off bigtime in the areas of power output and the longevity of your saw and especially SAFETY.

[RBW]

OK, heres the first step, Clean out behind the clutch and around the oil pump. This saw as you can see was neglected to the point that the chain was making nothing but dust, nary a solid chip in the bunch, and there WAS a bunch!











Heres the pile "O" Spooge that came out.










Once you scrape all this junk out, blow it out with some compressed air or hose it down with carb cleaner. After having done this you will find a black plastic plate. This plate is here to keep the majority of the chips out of the air gap. But what happens when you let the chips build up in this area?


They become soaked with oil!


Once this mess is soaked with oil the oil will then migrate behind the plate and into the gap. Once your gap gets all greasy, you never know what will get trapped in there.




Now were onto the flywheel side to dig in the gap. The first thing you'll need is a length of rope to act as a piston stop, I use braided nylon 3/8" diameter about 9" long.












Simply remove the spark plug and rotate the engine till your at TDC, then rotate 1/4 turn more. Now stuff about 1/2 of the rope in the cylinder. This will prevent the engine from turning and you can now loosen the flywheel nut and use your favorite method to remove the flywheel. ;D I'm not even going there.




Once you have the flywheel off you'll see your saws Air gap. You can see it in this pic surrounding the round ignition piece surrounding the crank shaft. This saws gap wasn't too bad considering how nasty the clutch side of the saw was, but when I dug down to the oily side there was some crud.


On this saw there was probably only a couple of tablesp oons worth in each of the two sections. And while this is not enough to cause this saw to over heat and boil the fuel, it was well on its way there.










*EDIT*


Just for the sake of clarification, heres a good pic of the air gap on a SXL, nicely outlined, courtesy of OldBigRed.







One side benefit of periodically disassembling your toys is that you get a chance to look for and eliminate problems before they can bite you or cause frustration. On this saw I found that a crappy repair that was made to one of the ignition wires was going to come undone. As soon as I wiggled the connection it broke and the tang from the coil came off.


If I hadn't found this I may have wound up putting the saw back together and frustratedly tried to start is thinking it was fuel related or a hosed plug, or worse the wire could have got hung up and ripped from its component part.




Now all I need to do is fix a few minor problems with the ignition and put her back together and this saw is ready to cut for another decade.



So there you have it, your saws Air gap demystified.

[gtor72]

my girlfriend thinks i am nuts for cleaning saws like that.
I say a clean saw is a happy saw!!!
and a better running saw...... ;D

[woodburner44]

You have sawa AND a girlfriend???

[TALLGUY]

I would have to say this was the first thing I learned that old homies need to run good is a cleaning. After all the big stuff is off I have found (I don't know just how safe it is) that a can of starting fluid works very good to take off the oily residue and leave you with just dry sawdust that can be blown off with just air. I get starting fluid for less than $1 a can so anytime I am cleaning up a saw I pull out a can and it dries almost instantly. Just have to have it outside and away from a source of ignition. Doesn't work quite as well as good brake clean but much cheeper. Iv never had it hurt the paint on any of my saws and have had it take crud off the nothing else wanted to take off.

[carmichael]

I've seen starting fluid used as a degreaser before but I don't think I'd use it for that. The ether in starting fluid has low boiling and flash points, wide flammable ranges(2 to 48% in air), low ignition temperatures and can form explosive peroxides when oxygen from the air bonds with the oxygen in the ether. Heat, friction, or shock can cause the peroxide to explode[/i]. So you don't need a open flame or spark as a scorce of ignition. Oxygen has been known to permeate the soldered seam in a metal container even without the container being opened. Ethers can become very dangerous in storage. You may save a buck or two using starting fluid as a degreaser but I don't think the risks are worth it.

::)Now someone tell me what the heck I just said

[wowposter]

Hi you big man.



Me love you long time.


Send me your extra spam here: [e-mail]

[chainsawwhisperer]

Wowposter, may your scaly hide be smote back to the fiery depths from which you came. CSW

[pioneer25]

Hello RBW
I am fairly new here and have over the last little while been nosing around the site.I have to tell you that is an awesome explaination of what you did cleaning out that crap.I need this type of tutorial as I am just getting started into tearing saws apart and working on them.I am as green as green can be but I like learning if it's made simple.I have various models of Pioneers and in various stages of repair some are in good shape just the way they are .SORRY no Homelites yet.Will the cause of boiling fuel in a Pioneer be the same proble?As I have come across this when using one fo my saws?
Many thanks
Lawrence
Keep it Coming

[chesterwin]

Hi all! Ressurrecting a sxlao I've had since the 80's. The electronic module went out last fall and since then I've replaced the module, carb., fuel line and filter. Currently have the cylinder off and am waiting for a new aftermarket pistion and rings. ( Couldn't locate NOS.) As long as I've had this saw I didn't know this area needed to be cleaned but will be sure to do so from now on. While she was down I bought 2 more sxlao's that are the old points and condenser versions. One still runs like the old homies are famous for and the other has to wait until the original "Big Red" is healed. Just got an sez to redo. Seems like it made some sense cause the chains can go back and forth between the 2 models if the same size bars are used. Thank's for the tips and keep em coming. Although not a total novice, I'm a homeowner user that's a believer in stuff that's built right. My wife says I should just use the Husky 350 she had when we got married.............right.................