# Question about a Ford 641 Workmaster that cuts out shortly after start-up



## chsmart (Aug 17, 2012)

Hi, I have a puzzling problem with my 641 Workmaster, which only began a few days ago. Prior to that everything OK, more or less. She starts up no problem, runs smooth, even under load (I'm dragging the York rake). After about 1 minute (maybe a little less) it starts to cough and quickly dies. Cannot start back up imediately, but if wait 15 mins, I can repeat the whole thing -- runs smooth for a minute then dies. I thought I maybe had a sticky float valve (carb is Marvel/Schebler TSX-765) so today I cleaned and rebuilt it, and for all my effort, I get the exact SAME results! Any ideas? I have heard about wonky coils that act up when engine starts to warm, and thus it is an ignition (not fuel) problem, but this makes no sense to me (I'm willing to be convinced otherwise, though...) Please let me know if you have any experience with this.

Many thanks.


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## sixbales (May 18, 2011)

To check for spark when it quits, pull a spark plug wire off of one plug and position it about 1/4" away fron the plug and leave it that way so you can see spark jump the gap. The spark should be a strong bluish arc. When it quits running, crank it to check if you can see spark jumping the gap. Orange spark is often not good enough.

There are a number of fuel screens that may be partially plugged, restricting flow to the carburetor.

1. There is a fuel screen attached to the shut-off valve under the fuel tank. This screen sits up inside the tank. Close the valve and disconnect the fuel line. Open the valve to check if you have strong flow from the tank through the screen. If not, drain the tank and clean the tank and screen.

2. If you have a sediment bowl, there is a screen that sits up inside it. Check that you have good flow through this screen. If not, clean the screen.

3. There is another fuel screen in the elbow at the inlet to the carburetor. Pull the bowl off your carburetor and check flow through the needle valve. If all you get is a trickle or dribble flow, clean this screen. 

4. If you have an (aftermarket) inline fuel filter, check for flow through it. If you've replaced this filter, you may have installed one that requires a fuel pump to force (pressure) adequate fuel through this filter. You really don't need this filter if the other screens are in place. 

Good luck. Let us know how you make out.


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## chsmart (Aug 17, 2012)

Thanks sixbales, you were right on the money. I took off the in-tanks screen filter, and found it to be deteriorated and clogged with particles of who-knows-what. Found the part at a TSC of all places, and replaced. While I was at it, I snaked out the metal fuel line and cleaned the screen above the sediment bowl, although that seemed fine. Reassembled, and all is running fine! I feel a little sheepish that this stumped me, but I DID have fuel flow, but I guess not enough to keep up. Now I know better what the stream should look like. Thanks again. Now I gotta go rake!


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