Tillotson carb help.

Discussion in 'Mechanic and Repair' started by mach9, Sep 22, 2003.

  1. mach9

    mach9 LawnSite Member
    Posts: 15

    I am working on an older Homelite Super 2 chain saw that has a Tillotson model HK carb. I have rebuilt the carb using an oem Tillotson kit. I have new fuel lines, clean filter, fresh fuel, properly vented tank, ect. This carb has an idle mixture adjustment, but no high speed mixture adjustment. I can make this thing idle perfectly with the screw about 1 turn out. But, at this setting, it will not run at high speed. Definitely acts as though it is starving for fuel. I can make it run at high speed with the idle mixture screw maybe 3 1/2-4 turns out, but then the idle goes away. I have found no way to make this thing run right at both low and high speeds. I have also cleaned the muffler and exhaust port and the engine itself seems to be in good shape as far as compression/leakage ect. Any suggestions would be greatly appreciated. Thanks. MJ
     
  2. ducky1

    ducky1 LawnSite Senior Member
    Posts: 252

    Check the inlet needle lever position that is under the metering diaphragm.
     
  3. mach9

    mach9 LawnSite Member
    Posts: 15

    Thanks, Ducky. I was advised by a friend to do that, and to raise the lever to increase fuel flow. That didn't help either. Is it possible I went the wrong way? As originally installed the lever was already above the surface of the body. The kit came with a new lever. I may install that just to get back to ground zero. I appreciate the help, though. Throw some more suggestions at me. MJ
     
  4. NCSERVICE

    NCSERVICE LawnSite Member
    Posts: 206

    I would get a can of carb cleaner and spray it around the seals, base gasket, and intake manifold while its running, it sounds like you have a air leak. at any rate homelites are disposable chainsaws.
     
  5. ducky1

    ducky1 LawnSite Senior Member
    Posts: 252

    When you rebuilt the carb did you take out the welch plugs and clean our the ports under them or just use the new diaphragms like most of us do?? Also where the high speed needle is supposed to be does it look like there is a blob of silicone sealent there? If there is dig it out and you will find a adjustment needle under it.
     
  6. mach9

    mach9 LawnSite Member
    Posts: 15

    Ducky,
    No, I didn't take out the welch plugs. But, this carb was very clean when I disassembled it. Just all of the gaskets and diaphram were very dry. Soaked it in a good commercial carb cleaner though.
    No, there is definitely not a high speed screw, or a drilled/tapped hole for one.
    I might try the welch plugs just to be safe though. Thanks for the help. Keep 'em coming! MJ
     
  7. ducky1

    ducky1 LawnSite Senior Member
    Posts: 252

    Hey Mach 9, How did your super 2 come out??
     
  8. mach9

    mach9 LawnSite Member
    Posts: 15

    Still working on it, Ducky. Luckily, the customer is not rushing me, so I've put it on the backburner a few times. Gonna pull the welch plugs next, and try to check it for air leaks. I'll let you know if I make any progress. Thanks. MJ
     
  9. Dave_B-The_Grass_Guy

    Dave_B-The_Grass_Guy LawnSite Member
    Posts: 18

    ANYTHING made by Homelite is disposable. Next time get a Husqavarna, they may cost more but you get what you pay for.

    If it were me, I'd tune it for max throttle, that's the RPM range where you do most of the work anyway, and set it for a high idle. Add maybe a 1/2 ounce of nitromethane (hobby store sell it as model airplane fuel) per gallon of gas/oil mix and it'll fire with 1 pull after choking it, and GOD will it ever scream!
     

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