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homegrown55

Homelite Trimmer w/ Zama C1U Carburetor

homegrown55
10 years ago

Ewalk....are you out there?? Failing Zama C1U H-39 carb is pushing fuel out of the small idle ports in the carb throat when pushing on the purge bulb. Therefore, it is drawing minimal amount of fuel from the tank. This carb has NO main nozzle. Cleaning and installing new G& D kit no help. Is the Idle circuit check valve the cause or...? I have tried to free it up with sprays of WD-40. I stay away from harsh cleaners on these to alleviate swelling the sensitive check valves.

Comments (7)

  • loger_gw
    10 years ago

    Have you tried ewalkâÂÂs patened, âÂÂA Few Ounces of Carb Cleaner in Your FuelâÂÂ? This has worked well for me on minimal carb cleaning needs for years.

  • ewalk
    10 years ago

    HG55 Normally with Zama carbs I use lucas top end fuel cleaner and conditioner . This has both solvency and lubricity required to gentley remove dirt debris and varnish from within the fuel circuits of these small carburators without damaging any internal parts . If the unit has ran recently normally as Loger has advised I simply add a few l ounces to the fuel mix , especially if the primer circuit has not been compromised . I run the unit via the primer or choke assembly and allow it to idle until the restriction is slowly reduced through the primary fuel circuits . If the carb is severely restricted a overnight soak is required but normally some compressed air and tag wire is used when mild restrictions are troublesome and the fuel treatment alone is not successful. Good luck and let us know how you make out Bro ! P.S. You have of course 1st ensured that the fuel lines and fuel filter are secure and not restricted ?

  • homegrown55
    Original Author
    10 years ago

    I haven't tried the fuel with carb cleaner in it and have never tried ewalk's Lucas approach. I did have it run on regular mix for a few seconds and die.It did that 2 or 3 times.At that point (w/ air filter off) I noticed fuel puddling in the air filter box. I figured it was flooding so I removed it and installed a G & D kit. Now the carb purge valve won't even work. It is neither drawing fuel, nor pushing fuel out.Maybe the check valves in the purge body need a good cleaning. I realize it does wonders and has worked before. I will keep you posted.

  • ewalk
    10 years ago

    HG55 Ensure also the smaller fuel line that enters the top of the fuel tank is also not damaged or pinched or cracked this would cause the primer bulb not to function properly . Originally you stated that fuel was evident within the venture or throat of the carb from the primer orifices. Also gasket 1st then the diaphram against the carb body lol :)

  • homegrown55
    Original Author
    10 years ago

    Hi again ewalk..I am glad you are still here on the forum. You and I have been to this rodeo before as I recall. The fact that the purge bulb was actually "priming" the carburetor (like on a lawnmower) was puzzling to me. I will clean, reassemble and reinstall fuel lines and keep ya'll posted!

  • ewalk
    10 years ago

    Hey HG what was the final verdict ?

  • homegrown55
    Original Author
    10 years ago

    Hey again Ewalk I was never able to get the check valve in the idle circuit to close. This inhibited the primer/purge bulbs ability to draw the correct amount of fuel. Someone stated in a post somewhere that they never worried about idle circuit checks but that function is critical to a carb which has only the Low speed circuit and NO main nozzle; as this one did. The primer base assembly on it was fine.....but I could not clear the check valve on the other end to provide the primer with the vaccum it needed to draw enough fuel. I really would like to see Baymees pics of the primer base assembly ball check and valve.The trimmers owner ordered another $15 Zama carb for it off of ole' eBay!

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