Engine cutting out

[padre]

Sorry about the length of the following post. I am not desperate. In fact, I'm feeling pretty good about the overall situation, but an old problem has raised its head. Maybe it's time to ask for some "troubleshooting" help from my friends here.

Today, August 12, 2019
After about 10 minutes of light mowing (no high grass) the engine began to cut out exactly as I have experienced intermittently over these last few years. This was more severe than usual. The engine actually died as I was in neutral, then sputtered all the way back to the shop.

The most puzzling aspect of all this is how well the tractor runs most of the time. The engine has not been “sputtering” constantly for two years. If I can remember it all I have done the following to troubleshoot this problem after it reoccurs.

+ thoroughly inspected and cleaned the carburetor.
+ removed the gas tank/hood and thoroughly cleaned it out
+ replaced the sediment bowl with new one – filter added in gas tank
+ replaced coil with new one
+ cleaned inside distributor cap
+ replaced spark plugs

With help from many of my friends on this forum I have recently replaced an exhaust pipe that was broken off right at the manifold and have replaced tie rod tubes and rods. I have also replaced the two large rear tires with new one and replaced a lost clutch access cover. These are really to keep the tractor operating, not as a restoration.

Now an old problem persists intermittently. I looked up my posts and was genuinely surprised to see that it was over two years ago I first sought help for this frustrating problem. I will not quote the full posts and the many helpful suggestions I received (most of them I tried to troubleshoot) but only the first line or two to show the continuing nature of this problem.

I do not find any posts between June, 2017 and August 6, 2019. Most of that time the engine was running normally, but then I would have this same problem again. Like the little girl, “when she was good, she was very, very good; but when she was bad she was horrid!”

Whatever thing or combination of things that is causing this can seem to “go away” for hours and even days so that eliminates many possible culprits that would now allow such periods of normal operation.

Post quotes below:

April, 2017
It has been running beautifully since then until a month or so ago. It will start and run fine, mowing and under full load and throttle--for a half hour, or sometimes almost an hour Not a problem, engine purring along. Then suddenly it will begin to "cut out" to the extent that I can hardly nurse it back to the shed.

May, 2017
Even better news this morning. I mowed for over an hour--heavy grass. Engine never sputtered, ran great. I quit because 1) weather getting darker, 2) at my age I work shorter hours, 3) no more mowing needed today.

June, 2017
I have moved several times since then without problems -- UNTIL this morning. Engine began to "cut out". I tried to finish a small section, but it got so bad I took off the sediment cup and emptied it.

June, 2017
Thank you for all the responses. I have not replied until now because the tractor has been running normally. I have mowed for a couple of hours without any "sputtering." I will try some of the suggestions if I have the same trouble again.

[Don McCombs]

When was the last time the points and condenser were checked/replaced?

[Jim Becker]

Add condition of spark plug wires to Don's list. I wonder if you have an electrical/wiring problem, maybe the ignition switch.

Get a piece of wire with alligator clips on both ends. Carry it with you. When the tractor acts up, clip it to the switch side terminal of the coil and the big cable at the starter. If it clears up with the added wire, you probably have a problem with the ignition switch or the wiring.

[padre]

Thanks, Don and Jim, I have been thinking that this is probably a problem with the wiring, especially because it happens only intermittently.

I have been putting off a real tracing of the wiring, but I'm going to do that first. I have even more been putting off really getting into the distributor and points--this scares me. as far as timing of the engine is concerned. I only consider such matter because I really do not have a mechanic to call on. I've just been trying to keep the tractor running enough to keep up with the grass and weeds.

Right now I have to attend to some ministerial matters. A minister who started out as my associate pastor and who later worked as an intern with me in another church. He is clearly facing his last days. He has been through two cycles of chemotherapy for cancer and after the last treatment his cancer has come back even more aggressively. He lives down near Houston and I am going down to see him, probably for the last time on earth, tomorrow. That is an all day trip for us. I will probably be holding his funeral not too far down the road.

I will continue to monitor this thread when I get back and will be grateful for all the help I can get.

[padre]

BTW, my name is David -- Williamson. That may be on my profile but this is to make that clear.

[Glen]

Hi,
I agree with Don, the points need regular maintenance. The engine won't run right when the points get burned enough.
A bad condenser can make an engine run bad also, or not run at all. Since you have replaced the coil, it is likely it needs the points and condenser replaced.
The new coil could be defective, anything is possible.

Try the jumper wire first, like Jim said, it is easy to do.

The Battery Ignition unit is not hard to work on. I've been replacing the points in my Cub for years.
The 1950 owner's manual has no info about the Battery Ignition unit. Battery Ignition came out during 1950 on Cubs, a little before yours was made, the info was not in the manual yet, evidently.
The info is in newer Cub owner's manuals.

Below are pages showing the unit, and replacing the points.
The 1st page shows how to get to the points and condenser.
Remove the distributor cap, move the cap out of the way, without removing any wires from it, it might go up on the oil filter cover, if the wires are long enough.

Then remove the rotor, the rotor pulls straight off the shaft, notice it's position first, it only fits fully on the shaft in 1 position. Then remove the cover over the points, it may be stuck in place, turn it back and forth and it will probably loosen.
The 2nd page shows the points, and condenser, and how to gap the points. You need a feeler gauge with .020"

http://farmallcub.com/rudi_cub/www.clea ... age-11.jpg

http://farmallcub.com/rudi_cub/www.clea ... age-12.jpg

Below is a listing for new points and condenser at TM Tractor. You can look at the pics.

http://www.tmtractor.com/new/el/367fp.htm

Sitting next to the engine is helpful. With the mower there, you can let the mower down to the floor, then put something on it to sit on.
You need a good light, to see in the Battery Ignition unit, a short screwdriver, with a sort of wide blade, and an 11/32" open end wrench, for the nut at the end of the point spring.
I put a large towel on the floor, to catch any small screws I might drop.

Remove the screw holding the left point, and the left point comes out.
Loosen the nut, and the right point slides out, off of the pin it pivots on. The point spring should have a slot, so it slides off the post.
Don't tighten the nut hard, there is a plastic insulator there, it can break if the nut is tightened hard.
Check the insulator there, in the side of the unit, sometimes they break, and then it can short there.
TM Tractor has new insulators.
Grease where it shows in the pic on the 2nd manual page, before putting in the new points. Grease should come with the new points, in a small capsule.

To set the gap, the right side point has to be on 1 of the high places on the 4 sided cam that turns.
If it is not on a high point of the cam, turn the engine, using the fan blades, until it at a high place on the cam, and the right side point is as far to the right as it will go.
Then use the .020" feeler gauge, and adjust the left side point until the gauge fits snugly in the gap.
Tighten the screw, and the points are set.

Put a few drops of oil in the end of the shaft, like is shown in the manual pic, it should have a felt there.

[padre]

Glen, as usual you are both encouraging and extremely helpful. I will print out this post and get back to it as soon as we return from our trip to Conroe. Thank you for responding to all my posts and for other of your post that I have read on search.

[padre]

Before I sign off for more than a day I will ask one question for all of you to consider. How can it run so well for so long with any of these fundamental problems? I have mowed for several hours in high grass and the engine has performed extremely well. Then, as this morning, I tried for only 15 minutes and barely got back to the shop. This is what is baffling to me.

[Glen]

Hi,
The points wear, and get more burned, the longer the engine is running. That is why IH said to replace them at the number of hours of use shown in the manual.

A condenser can go bad also, sometimes the engine runs bad, sometimes it won't run at all.

It's possible it's the wiring, like was said above.
The points and condenser are a good place to start, since they haven't been replaced lately.
My opinion.

[Dan Stuckey]

Just went through about the same deal as you're going thru now. What turned out to be my problem was a vacuum or suction in the gas tank as the vent in the gas cap had clogged up and the fuel tank wasn't being vented. The next time your problem happens, reach out and loosen the gas cap to see if the problem clears up. Interesting to when the problem occurs, jump off the tractor quick and loosen the fuel line at the carb to see if you have a good steady stream of fuel flowing from the tank. Hope its something as simple as this.

[Glen]

Hi,
Here is info about timing the Cub engine, using a timing light.
Cubs with Battery Ignition need to be timed with a timing light. The Cub service manual recommends it. It is not hard to check and set the timing.
Replace and gap the points first, if you are going to replace them. Changing the point gap can change the timing, so set the timing last.

You will need to buy or borrow a timing light first.
New ones probably come with directions for use. Here is some info for use.
They have 3 wires and connections.
1 connection clips on over the number 1 spark plug wire. This connection tells the timing light when the number 1 cylinder is firing.
The light is powered by the battery. Most timing lights are 12 volt timing lights, the directions may say if it is 12 volts.
2 connections connect to the battery posts. If it is a 12 volt timing light, you can connect it to a 12 volt battery, it will make the light brighter, and it will be easier to see the timing marks.
You have to use the light at the left front of the engine, which is where the timing marks are, so have the wires so they will reach to there.
Below is a timing light you can look at, I'm not sure if this one is still available. This is a lower priced one. You only need a lower priced one for a Cub.

https://www.ebay.com/itm/Petrol-Engine- ... ctupt=true

Below is a page from the Cub service manual showing the timing marks.
Point the end of the timing light at the pulley and marks, pull the trigger, the light will flash, and the mark number 1 in the pic should be aligned with the pointer, number 4.
The engine has to be running, and should be at slow idle speed, which is 500 RPM.
They are discussing other things on the page, use only the pic of the timing marks.

http://www.farmallcub.info/manuals/gss- ... 001-43.jpg

If the mark is hard to see, you can stop the engine, and mark it with white chalk, or a white marker.

A 1950 Cub probably has 1 timing mark, number 1 in the pic. IH started using 2 marks later. The number 2 mark is not a necessity.

If the marks are not aligned right, the timing needs changing.
You have to loosen the distributor so it will turn on the base. There are 2 clamps at the round base of the distributor. They have 1/2" heads. 1 clamp is on the engine side of the Battery Ignition unit.
I use a 1/2" box end wrench on end, between the engine and Battery Ignition unit to loosen the bolt. They only have to be loosened enough that the distributor will turn in the base.
Don't disturb the unit where it bolts to the engine.

Below is a page from the Cub parts manual. The distributor is number 14 in the pic, the clamps are number 3. It is not shown with the bolts in the clamps.

http://www.farmallcub.info/manuals/cub_ ... 012-26.jpg

You will have to recheck the timing, using the timing light, until the marks are aligned. When they are aligned, tighten the bolts, and check it again, to be sure nothing changed, and it is done.

The spark advance should work right, so the engine has good power, especially using a rotary mower.
That is probably one reason they have the number 2 mark on the newer pulleys. That is the amount it advances, up about to the number 2 mark when the engine is running at 1800 RPM, for a 1950 Cub.
You can check and see if it works by pointing the timing light at the mark, and see if the timing advances as you speed up the engine.
It should slowly advance as the speed increases, until it is where the mark would be, if the pulley doesn't have the number 2 mark. Good luck.

Be sure the vent holes in the gas cap are open, like was said above.

[padre]

This is all extremely helpful and encouraging enough that I plan start with the wiring and then try my hand at replacing the points and condenser (which I have just ordered from TM). I did mow this morning until both I and the tractor were ready to quit--it started "cutting out" after about 20 minutes, I cut out about the same time (see my post above about my friend and colleague). It was an all day trip, probably 700 miles, and I'm feeling the tired today. (My 86 years of life are manifesting themselves.) I am also preaching on Sunday and have decided to wait for my parts to arrive before "diving in."

OHH .. one question. These are extremely close quarters between the oil filter housing and the distributor cap. I question my ability to work on the points and condenser at that angle with my level of experience (which is near zero!). Which would be better: try it attached or remove the distributor? Which would actually be more difficult in the long run?

[padre]

CORRECTION. Maybe it felt like 700 miles but it was actually less than 500 miles round trip. Just shows how tired I am and how bad my math can be.

[Eugene]

Engine cutting out at about 20 minutes is a typical coil fault.

Changing points and condenser is not a difficult job. Be sure to read, understand, and follow all of the directions. Do the points and condenser first. Then, if the 20 minute engine fault reoccurs, change out the coil.

Cub tune up parts, gaskets, bearings, oil filter, etc., can be obtained from local auto parts stores. My favorite, local, auto parts store has these parts in stock.

[Pdurdon]

I’d lean towards points and condenser then possible coil failure when it gets warm.