Ford 841 Running Rough

[ARHunter]

I have a ford 841 that has been running great for a few years. The other day I was bush hogging and when I first started it up and started to move it started cutting out pretty bad for a few seconds and then it would start running fine. After a few minutes it seemed to start to run fairly normal, would only sputter every once in a while.

It has done this everytime I use it now. It seemed like a fuel problem but maybe not. I replaced the gas tank couple of years ago and the fuel flow to the carb is fine and the sediment bowl and screen are clean. I took the carb off hoping to find something wrong in there, but it was perfectly clean. I went ahead and put a repair kit in but when I started it up it still does the same thing. I also put in new plugs, points and condensor, dist cap and rotor and wires this spring. Once I get past the first few minutes of cutting out and sputtering it runs pretty good but I can't figure out what is wrong with it. Any help would be appreciated. Thanks

 

[old]

Does choking it hurt or help it?? What does the spark look like?? Will it jump a 1/4 inch gap or more at all 4 plug wires

 

[wfd2]

I'm having same problem with my 641. I checked fuel
flow and replaced coil. Adding some choke helps it
when it's sputtering and backfiring when idling
down. It almost stalls. Last night when it was
running poorly, I checked the sediment bowl and
found bubbles in the bowl. Does yours have bubbles
in the sediment bowl too?

 

[ARHunter]

No, I don't have any bubbles in the sediment bowl. I have good fuel flow. When it first starts to cut out, I can pull the choke, it will start to die, then pick back up and seem to run okay. Once it gets up to normal temp it seems to run okay except for an occaisionaly sputter. I bushhogged for 5 hours this past weekend after the initial problem.

I haven't checked the spark. It seems to run almost normal when warm so it didn't really seem to be an ignition problem but I'm not sure.

 

[ARHunter]

No, I don't have any bubbles in the sediment bowl. I have good fuel flow. When it first starts to cut out, I can pull the choke, it will start to die, then pick back up and seem to run okay. Once it gets up to normal temp it seems to run okay except for an occaisionaly sputter. I bushhogged for 5 hours this past weekend after the initial problem.

I haven't checked the spark. It seems to run almost normal when warm so it didn't really seem to be an ignition problem but I'm not sure.

 

[Billy NY]

What kind of ignition parts did you install, there are some inferior aftermarket junk out there. I've always installed Echlin and or what Napa sells and its always been good, I tried cheap parts off the web, think one of the rotors self destructed. The only issue I have is when the tractor sits, and not always, just did it recently, points must get oxidized slightly, and another handy tool Napa sells, is the the 5 or so little wire brushes on a ring, just take the small round one and brush those contacts, thats it. I do keep a cover over the tractor as well.

I think I'm into 2 years on the current set and it runs 50 hours or so a year, maybe a little more or less. Gap is .024 to.025 if I recall, always forget.

One thing to consider if the fuel system is not the problem.

 

[Will Gumbert]

You should probably check the spark as old said
(if you crank the engine while standing by the
machine, make SURE it's in neutral).

If thats OK then it sounds like it could be
running a bit lean. I believe the idle mixture
screw on your Marvel-Schebler carb (if thats what
it has) is the air-adjusting type which means that
turning it in or CW will make it richer at idle
and until you rev the motor up a bit and make it
pull. You said that you put a kit in the carb.
Did you soak it real good in carb cleaner and blow
out all of the passages with an air gun? Those
carbs need to be pretty clean to work right. -Will

 

[ARHunter]

I cleaned and blew out the carburetor while I had it apart. The symptons are exactly like they were before I pulled the carb off. I was hoping to find some trash in the carb, but it was very clean and I didn't find anything wrong in there. This carb does have the adjustable main jet which I have set at about 2.5 turns out. It doesn't really seem to affect it much until it is screwed almost all the way in.

It seems like if it was an ignition problem it wouldn't get better after the engine gets up to temperature. I have seen bad coils before that start to fail after they get hot. I have not seen one that gets better when hot.

I have an inline filter as well as the sediment bowl. I am going to run a new fuel line straight to the sediment bowl just to make sure there isn't a problem with the filter.

 

[JonB]

could be water in the gas.

 

[ARHunter]

(quoted from post at 18:37:50 08/23/14) could be water in the gas.

Maybe I should drain the tank and put some new gas in there. The day this thing started doing this, I put some lead additive in along with 5 gallons of gas. I wouldn't think that would cause any problems, but I suppose it could. I have probably run 10 gallons of gas through it since then so it seems like if there were any water it should be gone by now?

 

[old]

That lead stuff is just a worthless snake oil that does not even have any lead in it so that in its self could be your problem.

 

[old]

Many times what you did is not enough. You need to use a small wire etc to poke into all the jets. I use a torch tip cleaner tool when I work on carbs. Also that brass tube that sits at a 45 degree angle need to be pulled out and the hole it in poke out

 

[Will Gumbert]

Again, old is correct, there could be a plugged
passage or the main nozzle.

In my earlier post I was referring to the idle
mixture adjustment not the power adjusting needle.
Most M/S carbs (at least the later ones) have both.
-Will

 

[ARHunter]

I re-routed the gas line in front of the engine, something I have been wanting to do anyway. I know the fuel supply is good and the spark is good.

I have about decided it must have an intake leak that seems to seal after the engine warms up. I have ran it enough this afternoon that it is finally running about normal. I checked the intake bolts and I was able to turn them a little but not much, but it has to be something like that since I can not find anything wrong with the other common problem areas.

 

[ARHunter]

(quoted from post at 19:55:33 08/23/14) That lead stuff is just a worthless snake oil that does not even have any lead in it so that in its self could be your problem.

I use that stuff sometimes in some of my old engines, but the stuff I usually get is more like oil and this stuff I got the other day was different (like you said, snake oil). Sometimes I just mix a little 2 stroke oil in the gas for these older engines that were designed for leaded gas.

 

[old]

The fact that lead was used does not have any thing to do with how new or old and engine is it was an octane booster nothing more nothing less and was not needed. Your better off with adding a bit of ATF to your fuel then most any thing else

 

[ARHunter]

(quoted from post at 03:19:01 08/24/14) The fact that lead was used does not have any thing to do with how new or old and engine is it was an octane booster nothing more nothing less and was not needed. Your better off with adding a bit of ATF to your fuel then most any thing else

My understanding is engines produced after non leaded gas came about had harder valve seats and the older engines used the lead for valve seat cushion and lubrication?

 

[wfd2]

I had the exact same symptoms that you are talking about on my 641. I just fixed mine yesterday and it runs great. Check the ignition switch. Jump it out to see if this makes a different. But, jump it out at the terminal block. I checked my tractor early on and found a bad wire BEFORE the switch, between the terminal block and the switch, so jumping it out at the switch made no difference. It was only until I started wiggling wires while she was sputtering did I find the wire.

 

[ARHunter]

(quoted from post at 17:06:36 08/23/14) What kind of ignition parts did you install, there are some inferior aftermarket junk out there. I've always installed Echlin and or what Napa sells and its always been good, I tried cheap parts off the web, think one of the rotors self destructed. The only issue I have is when the tractor sits, and not always, just did it recently, points must get oxidized slightly, and another handy tool Napa sells, is the the 5 or so little wire brushes on a ring, just take the small round one and brush those contacts, thats it. I do keep a cover over the tractor as well.

I think I'm into 2 years on the current set and it runs 50 hours or so a year, maybe a little more or less. Gap is .024 to.025 if I recall, always forget.

One thing to consider if the fuel system is not the problem.

You nailed it. I was determined to make the fuel system the culprit since I had just installed a whole new ignition system, in fact I bought the components from this website. After rebuilding the entire fuel system including going into the carburetor 3 times, I just couldn't find anything wrong. I thought maybe intake leak, but decided that was not it either. This afternoon I took the made in China points and condenser out and re-installed the ECHLIN points I had taken out and it is running perfectly. Lesson learned, don't put cheap china made parts on if there is something better available. Thanks for all of your help.

 

[CAEMI]

I'd suspect plug wires. Old motors require copper core wires. If you don't have copper wires in good condition, start there. Copper wires are hard to find so most people use resistor wires. I'd even suspect kits that are "Made For" unless they say they are copper core.