Homelite Super XL-12 help needed.

Discussion in 'Mechanic and Repair' started by 1993lx172, Jul 3, 2013.

  1. dboyd351

    dboyd351 LawnSite Bronze Member
    Messages: 1,124

    After checking to make sure it has better than 100 psi compression and spark, the first order of business in fixing up most old saws involves replacing the fuel line, fuel filter and installing a carb kit. Between all the varnish and crud that accumulates in the fuel tank lines and filter, and the degradation in rubber/plastic parts caused by the ethanol in todays fuels (that the old saws weren't designed for), it is really false economy not to replace the fuel lines and filter. You may rebuild the carb and immediately have it go bad again by sucking up crud thru the old fuel lines. I know it is tempting to try the easy way and hope it runs OK, but it often costs you more trouble than doing it right the first time.
    Might want to go over your buddy's place with a six pack and watch him work on the saw. Could learn a lot.
  2. 1993lx172

    1993lx172 LawnSite Bronze Member
    Messages: 1,305

    Thanks for the advice,

    Spark is great it has the coil system rather than points and the on off switch works as it should.

    I was planning on opening up the gas tank (its a two piece deal) to make a permatex gasket as it seeps gas out of the bottom so I'll do that then. I may pull that felt wick out and use a modern in tank filter it just depends on what I find.

    It has pretty good compression and the piston and cylinder look to be in good shape with no scrapes or gouges. I don't have an exact number of the psi yet but as this saw was running the day before my grandpa bought his Husqvarna I'm not too worried. Worst case scenario I get a piston and ring kit on ebay for about $30 or so and have that shop put it in.

    The carb kit should be here in about a week so I'll get back to it then.
  3. 1993lx172

    1993lx172 LawnSite Bronze Member
    Messages: 1,305

    Well the carb kit came in today and in watching some how-to videos on YouTube, I can tell my diaphragms are bad as they are very stiff rather than pliable as they should be, and at least one gasket appears to be missing on my saw for some reason.

    Now there are two small concave solid metal disks in the kit one is half to a quarter the size of the other one, Anyone know what they are and how to replace them?

    It's a Tillotson HS 4C carb if that helps

    And the rebuild kit is a RK-23-HS. This kit if for any HS series tillotson carb
  4. dboyd351

    dboyd351 LawnSite Bronze Member
    Messages: 1,124

    The metal discs are welch plugs. I usually don't mess with pulling the welch plugs, but some people do, using a pick or small chisel type instrument.
    One thing I can tell you is it is a good idea to seal the edge of the welch plug using fingernail polish on the tip of a toothpick, even if you don't pull and replace the plug. Leaking welch plugs can cause erratic running.

    Sounds like you'll have solved at least part of your problems when you replace those diaphragms.

    Oh, I almost forgot to add - many of those kits come with extra parts because they are meant to cover a range of carbs, so they have the parts for all of them. Usually what you do is match up the old parts from the carb you have with the new ones from the kit and discard the extra parts. You might also want to see if you can get an IPL of the carb you are working on so you can match up the parts and order of assembly. It is easy to get the paerts in the wrong order and the saw won't runh right.
    Last edited: Jul 18, 2013
  5. 1993lx172

    1993lx172 LawnSite Bronze Member
    Messages: 1,305

    I'll try an look for an diagram online of how it goes together but after watching the how-to's it seems to be pretty easy, but I will definitely try and find that parts list first. I plan on laying everything out in the order I remove it on some clean copy paper and lay out the new parts on another then match them up before putting the thing back together.

    Is there anything behind those plugs that could be a problem, like a screen or a port that needs to be cleaned or replaced?

    I've got one yard to do tonight (just got home from my job/internship) and if I have time I may work on it.

    Thanks for the help so far, hopefully one of the next few posts on this thread are of a few pics of this thing sitting on a pile of wood it just cut up.

    That or it will be for advice on how to replace a piston and rings.
  6. dboyd351

    dboyd351 LawnSite Bronze Member
    Messages: 1,124

    My suggestion would be to leave the welch plugs in place, but seal the edges with fingernail polish. I believe there are sometimes check valves and sometimes screens behind the welch plugs, but I'm not really sure because I leave them in place. I get the impression trying to remove the welch plugs can easily damage the carb, so I rebuild the carb without removing them.
    I can tell you I've rebuilt a carb and it still wouldn't run right - was advised to go back and seal the welch plug with fingernail polish - did that and it ran great.
    If you want more detailed advice, go to Arboristsite -there are guys there that know way more than I do.
    Good luck, I'm definitely still learning myself.
    By the way, for some saws, a new carb can be almost as cheap as a rebuild kit.
    In spite of the fact that many Stihl parts are priced very high, I bought a brand new carb for a MS 250 chainsaw for $17.50. The rebuild kit was $12.95. Pretty obvious why I bought the carb instead of the kit.
  7. 1993lx172

    1993lx172 LawnSite Bronze Member
    Messages: 1,305

    Thanks I'll try Arboristsite and the nail polish trick. Just regular clear right? I'll see if I can borrow some from my mom or my sister when I go to do it.

    I looked and a New Old Stock carb was about $100 with shipping and a used one that may need a kit anyway was running about $30 with shipping. I was able to order the kit on Amazon for about $15 with shipping.
  8. dboyd351

    dboyd351 LawnSite Bronze Member
    Messages: 1,124

    Any nail polish will work, but I like to use a color (I use white), just because it is easier to see where you put it, so you completely cover the crack along the edges of the welch plug.
  9. 1993lx172

    1993lx172 LawnSite Bronze Member
    Messages: 1,305

    Okay time for a little update: The carb rebuild went good. Like I said the fuel pump diaphragm (the one on the top part of the carb) was stiff and stuck to the gasket and the metering diaphragm was about as pliable as the sheet of copy paper I set it on when I took it off. I replaced the metering pin and the little lever thing that goes from the diaphragm to the metering pin. Got it all buttoned up and started pulling on it. About ten pulls later....... it kind of popped once and raw gas started dripping out of the exhaust and when I pulled the engine to where the piston was at the bottom of its stroke the cylinder was soaking wet. At least most of the carbon looks to have been cleaned out.

    So now I went from having no gas to having way to much. But at least I know it's getting fuel. But I think I just need to open the carb back up and adjust that metering lever down to decrease the fuel flow. Plus I need to do that nail polish thing, it started to rain all of a sudden and it was a bit of a scramble to the get the saw together, my tools back in my tool box, and everything from the back patio to the garage.

    It was also blowing fuel about a foot and a half out of the exhaust.

    Note you should wait for a while for the fumes from inside the cylinder to dissipate before listening to your dad's suggestion of pulling the spark plug and checking the spark.

    So I think if I get it adjusted right it should be a runner. If not I can trade doing some deck plans for the guy at the small engine shop for some work. I also have some store credit from the equipment rental side of their business to use if need be.

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