641 Workmaster trouble

George.d · Jan 16, 2016

Hello all
I'm new to the forum and have been having some trouble with my 641 workmaster. This past fall the tractor would run great for an hour or so then would start to loose power under load. I had wanted to rebuild the carb anyway but decided to replace it instead. ( i'm telling you this because i don't think it is a fuel problem.) Tractor ran great for about a week then started to do the same thing. It would run for like 2 hours then start to putter and die under load. I checked for spark and am getting very weak spark. points, plugs, wires, and condenser have all been replaced. She'll fire but runs very rough and dies before i can even get her moved. Any input would be greatly appreciated. Thanks guys

old · Jan 16, 2016

I would try to the old condenser and see if maybe you have a bad new condenser which is common now days. If that does not help check your spark again at the center wire on the distributor. If it is not a good blue/white in color and jumps at least a 1/4 inch gap your coil maybe going bad. Had what your having happen to my 841 years ago. It would run good for about an hour then start to run poorly and I found it to be a bad coil

WayneIA · Jan 16, 2016

Put a value on the old carburetor. I wouldn't mind playing with it! Might even make it work. Email is open

cdmn · Jan 16, 2016

I agree. It takes a while for the coil to heat up and break down.
You could double check voltage with a volt-ohm meter. Ignition
switch also could act funny after warming up for a while.

Are you using 12 volts on a six volt coil or otherwise? Some coils need a voltage resister, others are built-in.

old · Jan 16, 2016

Not really a voltage resister but a ballast resister to use the correct term. Also no coil has a ballast resister built into them they are just wound different so as to be either 6 volt or 12 volt coils. Just for your info

markct · Jan 16, 2016

Could still be a fuel issue, the carb is not the whole fuel system, is tank clean, strainer bowl
clean and good steady flow from the fuel line?

dmbinva · Jan 17, 2016

12 volt coils come with or without an internal resister

old · Jan 17, 2016

No such thing as an internal resister they are just wound in a different way so as to make them a higher resistance by the way they are made to so external resister is then need but they do not have a resister is them

George.d · Jan 19, 2016

Thanks guys for the input. I plan to
replace the coil first and see what
happens.

dmbinva · Jan 19, 2016

(quoted from post at 16:55:30 01/17/16) No such thing as an internal resister they are just wound in a different way so as to make them a higher resistance by the way they are made to so external resister is then need but they do not have a resister is them

Well OLD I will put the answer another way some require an external resister and some dont

Sean in PA · Jan 19, 2016

(quoted from post at 14:14:08 01/19/16)

(quoted from post at 16:55:30 01/17/16) No such thing as an internal resister they are just wound in a different way so as to make them a higher resistance by the way they are made to so external resister is then need but they do not have a resister is them

Click to expand...

Well OLD I will put the answer another way some require an external resister and some dont

Correct!

641 Workmaster trouble

George.d

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old

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WayneIA

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cdmn

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old

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markct

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dmbinva

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old

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George.d

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dmbinva

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Sean in PA

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