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Why will my weed trimmer start but not stay running?

My weed trimmer starts but won't stay running. It is a Craftsman. model no. is 536773400.

Craftsman , Hand Gardening Tools
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2 Answers from these members:
Manage My Life
There could be several factors, but if it will start and run for a while then the most common reason for stalling out would be some kind of fuel or incoming air restriction. . The exhaust and engine would seem okay since the unit will run if you supply the fuel.

If manually adding fuel, by priming or adding some through the carb or spark plug hole, keeps the engine running relatively normally rather than stalling then it will further confirm restriction of the incoming fuel or air.

Check the air filter or try running without it to see if the problem might be an air restriction.

You can check fuel flow from the gas tank simply by putting the fuel line that normally goes to the carb into a can and turning on the fuel to confirm it flow freely through the line. If not then there is something blocking the line or tank outlet or possibly the tank is air locking due to a plugged vent in the cap.

This model uses a pressurizer system as a prime. That means when you pump the primer bulb it actually pushes extra air into the carburetor float bowl where the added pressure pushes extra fuel out into the air stream through the carb. So if there were any leak or problem with the prime it could be causing an issue.

That leaves the carburetor as the most likely problem area. Possibly some residue of fuel left in the float bowl has caused your float assembly to stick or is blocking one of the small jet openings. So the carburetor may need some attention or repair. We recommend carburetor work be done by a professional to assure the unit safely runs to its full potential and still meets all emission standards.

If you still are having problem then you might need to go back to engine basics as you might have something overheating, such as a coil, or some other issue. The basic troubleshooting in your

Owner's Manual

and in the link below should help further.
by Manage My Life
April 29th, 2008
0 votes
Manage My Life
I am no expert but a C1U-W19 is not a walbro carb it is a Zama carb Rb kit117 mod gnd64. you can find this on the Zama web site. It will list all zama carbs and cross referance to modle and size the modles whice I estimate is over 100 to the Rb # and the Gnd # which for the C1U-W19 Carb the RB-# is 117 the GND-# is 64 I had the same peoblem with my poulan pruner and I was working it as a Walbro untill I took the diaphram cover of and saw the name Zama. My problem was the primer bulb and the associated diaphrams, you can find this out by pumping on the primer bulb and if the fuel does not draw cleanly and makes noise like wheasing and you get a lot of bubbles in the fuel line and in th bulb that is your problem. It fixed mine and I didnt have to take the cab off. hope this helps.
by Manage My Life
October 6th, 2012
0 votes
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