Erratic leaf blower

My 18 year old leaf blower, an ancient Sears model, ran great until recently. It starts fine, it runs at full power just great, but when I turn down the throttle, it stalls. It then is almost impossible to start again unless I wait ten minutes and try again. It runs great at full throttle but every time I reduce the throttle, it stops and will not restart. Previously, when I throttled it back, it would just slow down and idle. I always add stabilizer when I buy a one-gallon refill of gas.
I checked the spark plug, looks fine. I replaced the fuel with new gasoline plus new oil, no luck. The manual says the carburetor cannot be adjusted.
Any idea what I should be looking for? Would like to keep the blower for another twenty years. :-)
Thanks for any help
Walter
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wrote:

As far as I know, most carbs have idle jets, and yours might have gotten restricted. I'd try some carb cleaner, but never did that with a 2-stroke. You might have to take the carb off to clean it.
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Vic

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wrote:

I had a string trimmer that was all messed up. Took off the air cleaner and sprayed carb cleaner into it. It immediately ran almost perfect. Only remaining issue is it will only develop about 50% power. As soon as I go past that, it starts dying and even backing off, it won't recover. It has air bubbles coming back in the return line from the carb, so I've concluded there is likely an air leak inside the carb. Haven't had time to go further.
But the carb cleaner took it from not running at all to running perfectly up to 50% of power which is good enough for what I need it to do right now. On Walter's it sounds like it's a clogged idle jet. In my experience, once a jet is clogged you usually have to take it apart to clean it. The above story was a notebable exception.
I'd also suggest tracking down a picture of the parts of the carb online to get an idea of how it can be cleaned.
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On 6/13/2012 6:08 AM, snipped-for-privacy@optonline.net wrote:

That's a symptom of the flapper valve not closing.
Haven't

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On 6/12/2012 9:14 PM, walter wrote:

There are different kinds of carburators. All the ones I've seen had some sort of adjustment. Sometimes they hide it behind a plug so the average joe can't change it and destroy the planet.
Sometimes there's a screw that takes off a side plate, under which is a rubber "gasket" with a layer of thin gasket applied. Sometimes you have to remove and disassemble the whole thing. The thin part covers a hole and makes a one-way valve.
What happens to mine is that the thin part curls up and the one-way valve becomes a two-way valve. Some say it's the alcohol in the fuel that causes it.
First, you have to find that valve system. Then you have to separate it from the two metal pieces without tearing it.
First thing to do is to practice. Take a 1/4" wide strip of paper and drag it at right angles across a 90-degree edge of your kitchen counter. The paper curls up.
You want to do the same thing to that little flap to cause it to go back flat, or curl toward the metal hole ever so slightly...without tearing it off.
Spray carburetor cleaner thru all the holes and blow it out with compressed air. That little flapper assembly won't like carburetor cleaner either, so blow it all out before reassembly. Make sure you don't get the gasket upside-down or the flapper won't seat on the hole.
I've used this technique successfully on chain saws and weed whackers.
YMMV.
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wrote:

first- Dump your gas-- and mix up fresh batch. Then try a tablespoon of K100 in the gas and run a couple tanks through it. http://www.k100fueltreatment.com /
Jim
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Some small engines, the insullation for the ignition coil breaks down. And won't run till the unit cools for a while. Briggs and Stratton had this problem on some lawn mowers.
Could also be that the fuel line goes too close to the engine, and you're getting vapor lock. Or, over heating. I'd start by cleaning the dust and crud from the engine, and the cooling fins. Water, simple green cleaner, and nylon brush.
Christopher A. Young Learn more about Jesus www.lds.org .
My 18 year old leaf blower, an ancient Sears model, ran great until recently. It starts fine, it runs at full power just great, but when I turn down the throttle, it stalls. It then is almost impossible to start again unless I wait ten minutes and try again. It runs great at full throttle but every time I reduce the throttle, it stops and will not restart. Previously, when I throttled it back, it would just slow down and idle. I always add stabilizer when I buy a one-gallon refill of gas.
I checked the spark plug, looks fine. I replaced the fuel with new gasoline plus new oil, no luck. The manual says the carburetor cannot be adjusted.
Any idea what I should be looking for? Would like to keep the blower for another twenty years. :-)
Thanks for any help
Walter
--
www.rationality.net




Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
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