50cc Weedeater / Strimmer - Starting and choke issues


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Old 05-11-19, 09:45 AM
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50cc Weedeater / Strimmer - Starting and choke issues

I have a 50cc weedeater / strimmer that I am having issues with and hoping you can help

It will only start if the choke is on and the idle screw is set almost all the way in, then it idles rough.

If you take off the choke then it suddenly increases RPM very high, then if you try and pull the throttle then it dies.

So far I have stripped the carb and cleaned it, it all looked spotless but cleaned it anyway.

Does anybody have any ideas on what I should be checking next?
 
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Old 05-11-19, 10:13 AM
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That is often a vacuum leak at either a mounting surface for the carburetor or at the crank seals. If the machine isn't too old the crank seals are likely OK. You can spray alittle WD40 around the intake gaskets to find the leak. The RPMs will change when it sucks in the WD 40.
 
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Old 05-11-19, 03:54 PM
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The machine is only 6 months old so I am assuming the crank seals will be good. I will give it a go tomorrow with some WD40 and try and track down the leak.
Thanks for the help
 
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Old 05-11-19, 04:05 PM
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If you took off the carb to clean it, you were likely having some gum up problems. There is a good chance either the carb to manifold gasket is damaged or the bolts are loose.
 
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Old 05-14-19, 05:06 AM
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Haven't managed to track down any leaks, sprayed WD-40 everywhere and no change in RPM.

Exact same behavior as last time, as soon as even a little bit of choke is turned off, the engine revs really high for a couple of seconds and then just dies.

I am starting from the bottom now and have stripped the gas tank down, just waiting for new hoses and a fuel filter to arrive then I will rebuild it. At least then I am certain that it isn't a fuel issue.
 
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Old 05-14-19, 05:53 AM
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It is almost certain a fuel problem. You're having a lot of trouble with a 6 month old machine. Could you post the model and make of the trimmer?

If you didn't find a vacuum leak some things that affect fuel flow are fuel cap not venting (usually it takes a short time before the engine stops), a damaged or stiff fuel pump diaphragm not pumping fuel, plugged fuel filter, incorrectly routed lines, plugged/dirty carburetor.
 
 

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