641 fuel issue?

Okay, so it seems like I solve 1 problem and another pops up...anyway, so my 641 starts on the first button push whether its hot or cold and I rarely have to touch the choke, and I can putt around all day and night below 1000rpm's.
I've cleaned the screen and jar on the sediment bowl, ive also pulled the sediment bowl and watched fuel flow and it comes out REAL fast and steady and I've tried pulling the gas cap, but it doesn't make a difference.
If I increase the rpm's slowly (on the throttle about 1000-1500rpm or more) it starts to run REALLY rough and sputter and acts like it wants to stall under a load but if I push the clutch in it will stop acting like its going to stall and just runs rough, if I try to increase the rpm's even more (anything above 1500rpm's) it will stall.
I've watched the sediment bowl while doing this and it always stays completely full of fuel.
I'm thinking its fuel related but not sure where to go, short of pulling the tank, on a side note, while doing a tune-up recently i noticed that there's no "spring" under the rotor, could that potentially cause a lack of spark issue?
Thanks
 
If the little clip under the rotor is missing then it will run rough. I'd lost mine once upon a time and tried to run without it - didn't go so well. It allows a lot of slop with the rotor, causing unreliable spark. I'd get one of those clips and go from there. They're apparently made of a really rare material...they aren't cheap for what they are... :-(
 
Thanks Ray, that's what I needed to know, looks like ill be tracking down a spring clip or whatever Ford called them.
I wondered why the manual showed one but this 641 doesn't have anything above the dust cover.
 
so your rotor is just ratteling around loose on the distribuitor shaft?

in the mean time, put a piece of masking tape ont he shaft and push the rotor down on it.. :)
 
At the time, I really didn't think much about it because the new rotor had a really solid and firm fit, it really wasn't loose at all BUT if there's nothing pushing the rotor up to the correct position or its sitting to low-if that's possible (which i suspect) then that would explain a lot.
 
I doubt the little clip is your problem. Better open up the carberator a half to three quarters of a turn.( The knob on the top front of the carb)See if that helps!
 
if it fits firm.. then its fine and it's not a rotor issue.

the rotor has a lil spring contact on it that touches the inside top of the cap.

as long as the rotor is not rettely loose ont he shaft.. it's not the rotor.

rough acceleration?

1, pull plugs and look at them.. if they are ashen white. you may be lean.

try this. tug on choke a bit when trying to accelerate. if it works better.. enrich the mainjet.

other things to look for.. make sure she is fireing on all cyls. when running above idle and sounding rough.. pull 1 plug wire and repalce at a time.. see if they all make a difference..and make about the same difference. if you find one that makes no difference.. or less difference.. that plug may not be fireing.. or that cyl may have an issue.. like stuck or burnt valve.s

a comp check may tell you more.

post back for details..e tc..
 
Well it maybe fuel or spark. Make sure you have a good spark that jumps a 1/4 inch gap. Next pull the drain plug on the bottom of the carb and make sure you have a good steady flow of gas for a few minutes. Catch that gas to look for water dirt etc. By the way if you adjust the main jet you should be able to open it up enough to get black smoke if you can not then the main jet is clogged up
 
. . .and, be certain that you have copper core wiring installed. I'm amazed the number of misfiring, backfiring, no firing problems that have gone away when I've taken those newfangled suppression wires off and put copper core on. Just accept that you're going to have to live with static on your radio. . .
 
Hello Bronco , As others have said get the Rotor Clip , make sure you have the Solid core wires and make sure you are using Autolite 437 sparkplugs not 216's . If you have changed over to 12 Volt gap the at plugs .035 not .025 for six volt spark will be hotter and keep the plugs cleaner with crap fuel we have today . Thanks Tony
 
I am using 216's, are those the wrong plug?
Wires are copper core.

I increased the main out about a 1/2 turn and I can increase the rpm's even more now but it still runs like garbage. Ill pull the plugs and look at em and also pull the plug wires 1@a time to see if any make a difference.
I have some Lucas gas treatment also is that okay to dump in the tank?
 
Wow!
Pulled the 216's and they were black, threw in some new 437's [email protected] and turned the main IN about a 1/4 turn (sitting at 1 3/4 turns out now) because I figured it was to rich and I could smell gas on start up.
It runs 100% better now, I can increase and decrease rpm's without it running bad and wanting to stall above 1500rpms, it's like a sewing machine now
 

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