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jniolon

craftsman blower problem

17 years ago

first post... need some help with my old blower. I've got a craftsman 37.7cc gas blower... model 636.796911 (1986 or so model)

It's quit on me... Put a spark checker in series with plug wire and I see an orange spark when pulling rope... took off the carb and cleaned it with aerosol carb cleaner and reinstalled... but it seems to be getting no fuel... there is fuel at carb inlet and in bowl when I remove the drain plug.... tried starting with a shot of starting fluid and nothing... I see the spark why won't it fire with start fluid ??? I'm dumbfounded... where do I look for the problem...

tia

John

Comments (7)

  • 17 years ago

    With starting fluid, you should at least hear something. But you said you have spark!!

    Remove the plug, close the choke,lock the trigger at wide open throtle and keep pulling. You should smell gas fromt the spark plug hole. If not, then something wrong with the fuel system. Do that first before you go any further. This also can verify you have spark. If you have fuel and spark, you should see something happen.

    Prime the bulb, if you see fuel moving, gas filter is good. If you see fuel return to the tank from the other tube, then the lines should be ok.....If that is so, it is pointing to the carb. With the age of the blower and being a cheap blower, might want to consider a new one.

  • 17 years ago

    2 cycle carbs need to be rebuilt periodically, it's just how they are. I would definately rebuild it. The only thing that might be tricky is setting the metering lever height, they vary by design. If you know what the carb is, someone here can probably tell you the correct setting.

  • 17 years ago

    Yungman ?? that's what has me puzzled... I removed the recoil starter and am using a cordless drill to turn the motor... with an inline spark checker in a daylight garage (no overhead lighting on) I can see an orange spark in the spark checker... and holding the plug against the head I see a spark... albiet not a strong one but a spark.

    I put the plug back in the cylinder and turn the engine with the drill while giving the open carb a shot of start fluid... and nothing.!!!

    Can I see a spark and it not be strong enough to ignite the s.f.???

    I'll try the closed choke/open throttle and see if I can flood it... but even if I don't I should still see some reaction to the start fluid, right ???

    thanks and will report later
    John

  • 17 years ago

    Don't use starter fluid. There is oil in the gas for a reason. It lubricates things that move and without lubrication, metal starts being picked up and redeposited where it was never meant to be. Ether has no lubrication. Ether is not good for a two stroke. Use the same mix that is in the gas tank.

    If you been using ether to start this thing on a regular basis, it probably has no compression to speak of. It probably doesn't have enough 'suck' to even get the ether into the cylinder and if it does it probably blows right by the piston. If you really want to know if it is dead, put a compression gauge on it and turn it over with the recoil starter, not the drill. Anything under 90 and it is a crap shoot if it starts but it will run when it starts. Anything under 80 and your arm is probably going to fall off before it starts. It is nearly 25 years old. I know they don't make things like they used to but I think you got your money's worth out of it--several times over.

  • 17 years ago

    Hey Jniolon
    You still have not tell me whether you smell gas with the plug off and crank. In your case, it is even easier with the electric drill. I just want to make sure you get gas in the normal operating condition......gas suck into the combussion chamber by turning the crank. This is to verify the carb is working.

    I don't care how high is the compression as long as you feel the resistance when pulling. Even low compression will give you a some response of trying to start. If it don't even responded, got to be either you are missing gas or spark. You have spark!!! The only other thing to check for spark is if you take the plug off with the ignition wire on, ground the plug to the engine cylinder and pull. If you see spark, it is all good. Forget about the spark, concentrate on the gas part.

    I am just not convinced that you get gas. You need to smell the gas from the hole after you pull a few times with choke on.

  • 17 years ago

    ok, here's the results... sorry it took so long.... work has been a bear and long days...

    first... removed plug ..closed choke, wide open throttle...pulled the cord 10-12 times... no fuel smell...

    second same test with plug in head... removed plug and it is dry... still showing spark on the checker...

    third... connected a compression gauge to the engine and pulled cord a few times... best compression was 40 psi...

    if it should be in the 90 # range... tells me things don't look so good for my faithful old blower... so it seems I have two problems... I'm still not getting fuel to the cylinder and low compression looks like one tired old blower...

    is it salvagable ??? worth the trouble ??? or should I pull the trigger on that sweet looking REDMAX I've been eying on the net ???

    thanks
    John

  • 17 years ago

    Before you give up on it, check the condition of you fuel lines. The fuel lines have a bad habit of cracking/splitting right at the end of the barb fitting on the carb. SOmetimes it is so small you can't really see it unless you are looking for it. I would visit the local repair shop and get a length of Tygon and replace the lines before I chunk. It will only be a couple of bucks. Ether is really hard on a two stroke. It wipes all the lubrication out of the cylinder and then it is metal on metal.