641 Dying Under Load

Zack Methvin

New User
Hey guys,
I have a 58 Ford 641 Workmaster. The tractor has been semi restored and runs perfectly at idle. However, The problem is that while under a load (5ft. finish mower) it slowly starts bogging down and dies. This happens instantly and without warning. It is not a gradual thing. I can riding along mowing just fine and all of sudden it starts bogging and keeps on until it dies. We have replaced the following to date:

Cap, points, condenser, rotor, plugs, wires, coil, NEW carb, flushed tank, pulled distributor-cleaned and lubricated.

I have noticed the while it is bogging down the governor rod never moves, is this normal? This thing has driven me insane and still cannot find the problem.

Any ideas?

Thanks
Zack
 
couple questions.

when you hit a area of more load.. like thick grass. does the gov open the throttle butterfly some or no?

when dieing.. has the throttle lever slipepd down any?


does tugging on choke help any?

will it immediately restart.. or need time before restart?

have you checked spark before start and at moment of stall?

checked fuel flow at/thru carb at stall?


noticed any water or fine debris in sediment bulb?

post back
 
when you hit a area of more load.. like thick grass. does the gov open the throttle butterfly some or no? Mostly when i'm going uphill

when dieing.. has the throttle lever slipepd down any? no, the throttle rod never moves.


does tugging on choke help any? Yes, i have to run the choke half open to make it run smooth.

will it immediately restart.. or need time before restart? most of the time it will restart

have you checked spark before start and at moment of stall? no, haven't checked the spark yet.

checked fuel flow at/thru carb at stall? no, how would this be accomplished? It bogs only while i'm driving it.


noticed any water or fine debris in sediment bulb? No, the fuel and bowl is always clean.

Thanks for the help.
 
if you have not checked spark.. you are getting ahead of yourself.

check spark.

checking fuel to carb and thru cab is easy. you will need to remove the fuel line to the bowl. heck.. i pull the banjo bolt too to mke sure it is open.

carb bowl has a drain as well.


you might be getting tank vacume as well...
 
As sound says check spark and make sure it is a good blue/white and will jump a 1/4 inch gap or more.
Then check fuel flow by pulling the carb drain plug and let it flow for a few minutes. Catch it so as to look for dirt etc.
If choking it helps you might try opening up the main jet a little bit till you find the sweet spot
 
I will follow up on all your suggestions and report back. If i am getting "tank vacum" how do i fix that? I don't even have a gas cap on it at the moment (lost it).
 
then it's obvious you aren't getting tank vacume.

with that .. i think you might want to ask for some local help to fix this.
 
The governor should move if the RPM drops until the motor gets back up to speed again. While you are using the mower the RPMs on your engine should stay pretty close to constant. When I got my 641 the governor was not working and I didn't realize it - I was constantly adjusting the throttle with the load and assumed it was normal. It made it tough when the load suddenly changed. The roll pin that attaches the governor arm to the governor assembly under the front engine cover had broken. You might want to try pulling back on the governor arm when the engine is running and see if it resists. If not then you may have the same issue mine had. You might also need to adjust the governor per the service manual's instructions.
 

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