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Echo trimmer---what have i forgot.

Discussion in 'Mechanic and Repair' started by themow, Jul 24, 2008.

  1. echoman8

    echoman8 LawnSite Senior Member
    Posts: 293

    I'm getting old and senile.

    What you have posted definitely indicate a rich condition rather than lean.

    I have had erratic problems when the valves in the purge pump are bad. I do not remember a consistent rich problem though. The long comedown on throttle has happened, but most of the time it causes me to adjust the carb often. It will usually run lean for a while, then rich, lean, rich .......

    OK what can cause it to run rich? Too much fuel or too little air.

    Since it has a preset jet for high, the only thing that can happen to the jet is to get stopped up or partially blocked (lean condition).

    The fuel is restricted until it gets to the needle in the carb. So, this is the only place it can get too much fuel. I have already covered the needle lever adjustment.

    I have two guesses.
    a: The metering needle is damaged on the tip allowing too much fuel in.
    b: The carb is off of a larger trimmer/saw. Check throttle butterfly screws for screwdriver marks.

    Too little air. The only place the air is restricted is at the air filter.

    Out of the box thoughts. There is a vent hole on the metal cover that captures the metering diaphragm (needle side). Make sure it is not stopped up. The carb depends on a vent hole through the cylinder and into the crankcase to get vacuum and compression which flutters the diaphragms. The hole into the cylinder will be where the intake gasket mounts. Should crud partially block this hole allowing pressure (and not vacuum) to the metering diaphragm, the needle would remain open. Not likely, but your problem is not common.

    I hope you solve it and please post the solution if you do. It is very unusual to have a rich problem without a quick solution.

    Good luck
  2. mngrassguy

    mngrassguy LawnSite Silver Member
    Posts: 2,167

    Maybe a dumb question but have you replaced the fuel lines? Mixed fresh gas?
  3. themow

    themow LawnSite Member
    Posts: 41

    tried fresh gas but didnt replace the lines

    echoman, i made sure i cleaned the vent hole, i thouht that it may have been my problem but it wasnt. im going to go outside and fool around with the needle. I know the carb is the one that came with the unit
  4. themow

    themow LawnSite Member
    Posts: 41

    Im going to make sure the needle isnt lifting up too soon. Im pretty sure the tip of the needle is in good condition. This has become more of a personal battle than anything else now...i dont want to lose.....Should i invest in a rebuild and repair kit??
  5. echoman8

    echoman8 LawnSite Senior Member
    Posts: 293

    Hi, Yea, this thing is personal with me now too.

    Yes, I would invest in a carb kit. And I would at least try putting a piece of plastic under the purge bulb. I cut a piece of freezer bag, poke a couple of holes in it for the bolts, place it underneath the bulb and plate and bolt it down.

    Since you are buying only one carb kit, seems like some local place would cost the same because of shipping. A friendly mechanic in a shop will have some good used diaphragms he has saved and may give some to you when asked. This happens often. I have several hundred new and barely used diaphragams my self.

    Good luk Echoman

    If you are determined to not buy the kit, then at least soak the diaphragms in Berryman carb cleaner. Soak them to the point that they are no longer stiff. If you soak them too long, they will expand. This is a temporary fix. In a few days, the diaphragms will stiffen again, but, they will work properly temporarily.

    Im going to a jobsite in the texas mountains tomorrow. Dont know when I will be back online. But keep me posted.

    Stick in there you will win,

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