Starts, Runs, Dies, Repeat

[Julien]

Hello,
I took the Cub out today to haul a load of compost. It started fine, ran fine to the compost pile, and then started fine again leaving the pile. Halfway down the driveway, in first gear on a slight incline, it stalled out. I started it back up, it ran for another 30 yards or so, and stalled out again. This pattern repeated at least five more times over the course of a couple of hours. The final time that I got it to start, it ran for a mere ten feet or so, stalled, and would not even start again. Twice, coming back up the driveway, it almost stalled and then recovered. Now it is stuck outside my garden overnight in the rain until I can get at it tomorrow with the battery charger. So sad. Hopefully it will start and run long enough so I can at least get it back in the shed. I recently replaced the spark plugs with a brand new set of Autolite 386, which seemed to solve the previous issues I was having with starting and running. The spark plugs really seemed to make a big difference, the tractor started up better than it ever has since I have owned it, but all improvements seem to have vanished. Maybe the aftermarket carburetor I put on two years ago is complete trash? Why does the tractor run fine and then just peter out? Why does it start and then not start? The Cub ran very well when I first got it and after I put on the new carburetor; I don't understand what changed. Not sure if this is indicative of anything but sometimes when I pull the starter there is smoke that comes out of the oil tank from underneath the cap.
Thanks,
Julien

[Don McCombs]

Check three things. First, make sure that you have sufficient fuel to run the tractor on an incline. The fuel outlet is at one end of the tank. Second, check the fuel outlet in the tank for debris blocking the hole. Then check the main metering jet for obstruction. It is the brass, hex head fitting on the side of the carb.

[Eugene]

How long is the initial run time? 2 minutes, give or take, fuel. 20 - 30 minutes, ignition problem, most likely coil.

[Glen]

Hi,
It is common on Cubs that the ignition coil partially quits, or the condenser can partially quit.
Then the engine runs for a while and quits, then later it will run again, over and over.
When it quits, I would test the power of the spark going to the spark plugs.
Below is a post I wrote on telling how to test the power of the spark the coil makes, if you need it.

viewtopic.php?f=1&t=114522

Or it may have a gas flow problem, like was said above.

If you mean that fumes or smoke comes out the breather, on the top of the dipstick tube, on the left side of the engine, that would just mean that the piston rings are not sealing as good as they should, or the engine is worn.
The rings can get stuck, and still be good. If they are stuck from goop on them, they have said on here to try Seafoam oil additive in the motor oil. It can help free the rings so they seal better.
They sell it at auto parts stores.
One expert on here said to use it for 2 oil change periods, and make the engine work, and get warmed up. If the rings are wornout, the Seafoam won't help much.

[inairam]

If you decide it is in the ignition not a fuel issue I have been getting my points and condensers from NAPA. I have had a lot of issues with ignition parts for the tractor web sites.

NAPA part number

Distributor Cap Part # ECH IH350
Distributor Condenser Part # ECH IH200
Contact Set (Points) - Magneto - or battery Ag Part # ECH CS1600
Distributor Rotor Part # ECH IH300

[Waif]

Multiple systems can be suspect.

Ignition/electrical.
Fuel.
Mechanical.

Your symptom might be more fuel starvation than a bad coil. And it can be a bad coil.
Choose a system and go through it.

Coil check. Condenser check. Have been mentioned. Be sure your points insulation at thier base is not broken and causing intermittent grounding. And that your points are clean.
Use known quality replacement parts ONE at a time and test after. You change eight things and find out the tractor runs worse , how do you know what
component made it worse? If you replace a working but worn ignition component save it. It might come in handy when a new replacement is suspected of failure or not to spec. in the first place.

Gasoline needs air to create fuel your tractor can inhale and combust. Starting at the tanks air intake to feed by gravity. Is your gravity route as designed?
Gas needs to go through tank and multiple other things before your carb. All factor. Even a line being too hot can mess things up.
Your air filters oil gets enough water in it and it can ruin your tractors performance. So can bugs ,ice,snow..
How so many large bugs got in one oilbath on one of my tractors....I can only guess a previous owner ran it and stored it without a cap.

Your linkage binds or is out of adjustment?
You adjusted your proper linkage after you replaced the carb?
Your carb's plate is moving the way you think the choke rod is controlling it? If you have not looked , I'm not sure it is.

I'd check your plugs. How they look might help.
And the mention of cleaning your main jet I'd do first.
I keep a wire for that on one of the tractors. Was tempted to tie a wrench on it too! But got the fuel system clean enough it wasn't icing up like prior. Substitute dirt or rust or rubber or who knows what for water and jets get restricted or clogged.

Your carb was either set good enough before you got it , or you adjusted it.
I wouldn't yet , but the float could be corroded or have a leak. That's a much later consideration to me. But I am more likely to make a carb worse than better when parts are sensitive..L.o.l..

[Julien]

As always, thanks so much for the input.

How long is the initial run time? 2 minutes, give or take, fuel. 20 - 30 minutes, ignition problem, most likely coil.

More like two minutes. I was able to get it back in the shed yesterday morning with some battery boosting and then charged the battery all day. It started up fine yesterday afternoon, ran for a little, and then just stopped. So, I guess I will focus on the fuel aspect for now.

Not sure what this means, but the fuel in the fuel bowl has a two toned appearance. I have been treating the gasoline that I put in, so I assume that is the orange layer on top. Underneath it is clear. Is that water? If yes, that's not good at all, right?

I'm probably due to change the oil and clean out the oil in the air filter. I didn't realize that could affect the running performance. Looking at the air filter bowl briefly, it is completely caked in old oil, as is most of the engine for that matter.

Check three things. First, make sure that you have sufficient fuel to run the tractor on an incline. The fuel outlet is at one end of the tank. Second, check the fuel outlet in the tank for debris blocking the hole. Then check the main metering jet for obstruction. It is the brass, hex head fitting on the side of the carb.

The tank was almost full, but that is good to keep the fuel level in mind as I live on the side of a mountain.

How do I check the fuel outlet in the tank? Do I have to drain the fuel?

As far as checking the metering jet, I unscrewed the hex bolt on the side of the carb, and then there are two holes, one that runs side to side and one in the end. Not sure which does what but they both seemed clear. I stuck a piece of wire in the hole on the end.

As a side note/question for all of you experts: will there ever come a time when this tractor will operate consistently as designed? Meaning, how much maintenance is necessary to keep this thing running well? I don't have much mechanical experience nor a ton of time to work on tractors, but I do like this Cub and I don't want it to feel left out of farm operations. Also, one of my neighbors tried to talk me out of buying it from the other neighbor, and I want to prove him wrong.

Thanks,
Julien

[Eugene]

The fuel in the fuel bowl has a two toned appearance. I have been treating the gasoline that I put in, so I assume that is the orange layer on top. Underneath it is clear. Is that water? If yes, that's not good at all, right?

Right. Most likely condensation - water.

Empty the sediment bowl and then install deicer in the fuel. From the auto parts store. Named Heet, gas line deicer/dryer, similar. Will remove water from the fuel system - actually burns it.

I wouldn't drain the entire fuel tank. After emptying the sediment bowl and adding deicer/dryer, I would drain a bit of fuel/water from the carburetor, perhaps a cup. The gas line dryer should take care of the rest of the water in the fuel system.

[Don McCombs]

How do I check the fuel outlet in the tank? Do I have to drain the fuel?

No need to drain fuel. Remove the fuel cap. With a flashlight, look below the filler hole and you will see the outlet. Check for rust, dirt and debris in the hole. If you find anything, attempt to siphon it out with Tygon tubing.

[Eugene]

Siphon it out fuel, with Tygon tubing.

I use a marine primer bulb and fuel line hose.

[Waif]

As always, thanks so much for the input.

How long is the initial run time? 2 minutes, give or take, fuel. 20 - 30 minutes, ignition problem, most likely coil.

More like two minutes. I was able to get it back in the shed yesterday morning with some battery boosting and then charged the battery all day. It started up fine yesterday afternoon, ran for a little, and then just stopped. So, I guess I will focus on the fuel aspect for now.

Not sure what this means, but the fuel in the fuel bowl has a two toned appearance. I have been treating the gasoline that I put in, so I assume that is the orange layer on top. Underneath it is clear. Is that water? If yes, that's not good at all, right?

I'm probably due to change the oil and clean out the oil in the air filter. I didn't realize that could affect the running performance. Looking at the air filter bowl briefly, it is completely caked in old oil, as is most of the engine for that matter.

Check three things. First, make sure that you have sufficient fuel to run the tractor on an incline. The fuel outlet is at one end of the tank. Second, check the fuel outlet in the tank for debris blocking the hole. Then check the main metering jet for obstruction. It is the brass, hex head fitting on the side of the carb.

The tank was almost full, but that is good to keep the fuel level in mind as I live on the side of a mountain.

How do I check the fuel outlet in the tank? Do I have to drain the fuel?

As far as checking the metering jet, I unscrewed the hex bolt on the side of the carb, and then there are two holes, one that runs side to side and one in the end. Not sure which does what but they both seemed clear. I stuck a piece of wire in the hole on the end.

As a side note/question for all of you experts: will there ever come a time when this tractor will operate consistently as designed? Meaning, how much maintenance is necessary to keep this thing running well? I don't have much mechanical experience nor a ton of time to work on tractors, but I do like this Cub and I don't want it to feel left out of farm operations. Also, one of my neighbors tried to talk me out of buying it from the other neighbor, and I want to prove him wrong.

Thanks,
Julien

It can be the ignored maintenance that causes the most trouble.
You can grease when required. The signs will be obvious on equipment not lubed as it should be.

Cubs with long lives have varied wear. And had varied care.
A Cub tuned up and maintained can see a long run. Hey , over seventy years old and I can hop on and work. That says something.

Part of that age can involve "personalities".
I have one tired Cub that will toast a coil when working it hard (hard!) on hot summer days. Does that make it undependable?
I've learned how to replace a coil in the field. And that hot days I'm not too crazy about working in , that Cub isn't either. We're not young and fresh no more..
I have not tried adding a fan , dry ice or wet rag to the coils housing. I just leave that Cub home on hot days.

Your Cub has a reason for what it's doing. That doesn't mean it's not dependable.
As mentioned it could be the condenser. Find quality condensers and replace yours and try it.
You'll want spare (quality) components for your next tune up. But having them prior allows replacement of a bad one just in case. Extra points in case you kill a set when dressing them or they get burnt from a racoon pulling the ignition switch and not putting it back. (Hey , mysteries can happen..)
You learn the tractor , have parts on hand and keep maintenance up and you reduce downtime.

You can kick the Cub to the curb.
Someone who knows Cubs can take it off your hands and have it running like a swiss watch. Or at least purring like an old machine designed well.
Or you can do it.
Respect for the gents that built it. It's design and limitations. And understanding how it works it is a lot easier than a lot of more modern tractors to learn.

Had a much newer diesel ten times or more the $value of my worst Cub the other day give me fits a while when I wanted it to be working. Wasn't because it was a diesel and fuel any issue , and I'm still not sure which of two things I frogged with was causing the condition of rough running , no acceleration without bogging with very limited acceleration , and stalling.
Someone who knows the model might have "fixed" it in seconds. Took me far longer. And nothing was replaced. A maintenance issue? Or just time to replace a component beyond any tune up?
Cubs have less numbers of circuits and components to go wrong. But still need to be in spec. and usable condition.