not starting after gasket replace + cleaning of carb

[marshall]

It was running fair but has been difficult to start of late so I was expecting some kind of project soon. After running out of gas and not starting after refill I determined I better look at the carb because it seemed like a gas issue.
The gasket between the two halves of the carb was totally worn out. I was very careful not to bend anything in taking it apart. I put in a new gasket, used gumout to clean what I could, ran a wire through tubes and main jet and then reinstalled expecting it to roar into life. Not so.

It still won't start. Maybe it wasn't a carb problem. The plugs were old and pretty covered with gas when I took them out. So I replaced them with new ones. Still not starting. My tractor repair guy down the road died this year and now I'm on my own and out of ideas.

What's the next thing to check/fix? Spark? How? It's a 1950. I've never done engine repair beyond this level so setting timing, knowing if I have a magneto or not, etc, are all going to be learning projects. A friend mentioned "changing points" once but I don't really know what that means or if it applies here. Hoping I can be stepped through this. I can always post video but there's not much to see or hear at this point except for the engine cranking and cranking but not catching at all. I guess it isn't just flooded...

[Glen]

Hi,
Cubs are easy to work on, you can probably learn how to repair them.

The gas flow could be slow or stopped, so the carburetor doesn't get gas. Be sure the fuel valve on the gas strainer is fully open.

I would do a fuel flow test. Be sure the fuel valve is fully open, remove the small plug on the bottom of the carburetor, and catch the gas in a large, clean can. Then you can put it back in the gas tank later.
Lots of gas should come out first, that is what is in the carb, after that, it should run in a steady stream, without stopping. Test it for about 1 minute. Put the plug in when done. Tighten it gently, the carb is soft metal, and threads can strip.
If the flow is not good, it needs improving.

Look at the gas strainer, under the gas tank. It could be dirty and need cleaning. There should be a screen in it, above the glass bowl. The screen can get dirty and slow down the gas flow.
It is easier to get to if you move the Touch Control arms to the rear first, but the engine has to run to do that.
If the gasket for the bowl is old, it might not seal if you reuse it.

TM Tractor has a new gasket and screen.

Yes, Cub ignition systems have ignition points originally.

Below is the 1950 Cub owner's manual. It has much info about operation, maintenance, and lubrication. The experts on here recommend reading it. There is a table of contents on page 1.
It shows what the magneto is, starting on page 30.
The gas strainer is shown on page 25.

http://farmallcub.com/rudi_cub/www.clea ... index.html

The Cub might have a Battery Ignition unit, and not a magneto. Battery Ignition came out during 1950 on Cubs, at serial number 115403. But some that had a magneto have had a Battery Ignition unit put on by people over the years.
The Battery Ignition unit is not shown in the 1950 Cub owner's manual, it is in the 1955 Cub owner's manual. Both units use the same distributor cap, points, and condenser.
Below is a pic of a Battery Ignition unit. The voltage regulator is to the right of it, you might not have that, it came out during 1950 also.

[Waif]

It was running fair but has been difficult to start of late so I was expecting some kind of project soon. After running out of gas and not starting after refill I determined I better look at the carb because it seemed like a gas issue.
The gasket between the two halves of the carb was totally worn out. I was very careful not to bend anything in taking it apart. I put in a new gasket, used gumout to clean what I could, ran a wire through tubes and main jet and then reinstalled expecting it to roar into life. Not so.

It still won't start. Maybe it wasn't a carb problem. The plugs were old and pretty covered with gas when I took them out. So I replaced them with new ones. Still not starting. My tractor repair guy down the road died this year and now I'm on my own and out of ideas.

What's the next thing to check/fix? Spark? How? It's a 1950. I've never done engine repair beyond this level so setting timing, knowing if I have a magneto or not, etc, are all going to be learning projects. A friend mentioned "changing points" once but I don't really know what that means or if it applies here. Hoping I can be stepped through this. I can always post video but there's not much to see or hear at this point except for the engine cranking and cranking but not catching at all. I guess it isn't just flooded...

A picture of your tractors right side, (right side being from operators right when on the seat facing forward) showing your distributor cap ect. will help.

Choose a circuit , or system one at a time. Fuel is as mentioned a good one to go through in your case. To confirm your fuel flow is good. Or to fix it.
Safely peek in the gas tank with a good flashlite and see what your fuel outlet and tank bottom looks like.
Then go to the view below your tank and follow Glen's instruction about your fuel bowl. (A fuel bowl is stock) , some owners have removed them though so if you have a question shoot.)

Your ignition system you can service most of the regular maintenance of. Worth learning ,and you will like knowing how it works ,how to keep it in good shape. Keep in mind ,most of what You do gets much easier after doing it a couple times. Again ,patience helps. You get stuck ,take time off and research the issue.

Finish what ever circuit or system you are working on before starting on another. Keep track of what you change. Save all old parts till system or circuit is confirmed good. A know good part replaced during a tune up can be labeled as such and saved for trouble shooting later if such a part is suspected of not behaving properly.

Replacing good ignition parts is a way to know fresh ones are above major wear limits/conditions for longer periods of time. Having a part give up/fail when you really wanted to just go vroom ,vroom instead will happen eventually if normal wear of ignition parts is not considered and replaced in a timely (hours/conditions) fashion. And sometimes...A part just fails for a reason other than wear.


You have found a great resource with Farmall Cub site here.
Be patient and review a process before starting on it. Some things affect other things if you move an items position ,or adjustment.

A tune up is fairly straight forward. A good thing to consider. Points are part of that.
Don't feel overwhelmed. A bite at a time you can do much with your Cub.

First determine your tractors ignition type before diving into what to do with it. Learning about other types can be done later if desired.
Once fuel flow is clean and good ,a basic tune up might go far in your Cubs health.

[marshall]

Thanks. I'm pretty sure gas flow is good. I replaced fuel bowl gasket and screen earlier this year; it's clear of residue. Gas flows freely out the line just before entering into the carb. When I crank the engine I see drops of gas coming out the bottom of the carb from its drip hole. So I'm fairly certain gas is getting into the carb. But I don't know if its correctly reaching the cylinders from there. When I crank (esp with choke on) I do see a steady white exhaust coming out of the stack which makes me think something is burning but engine isn't catching. So is there more to check in the fuel system or do you think its time to move elsewhere? Heres a pic of the ignition system. Maybe you can tell me what I'm working with

[staninlowerAL]

J4 magneto, std on cub until introduction of the battery ignition.

[Waif]

Thanks. I'm pretty sure gas flow is good. I replaced fuel bowl gasket and screen earlier this year; it's clear of residue. Gas flows freely out the line just before entering into the carb. When I crank the engine I see drops of gas coming out the bottom of the carb from its drip hole. So I'm fairly certain gas is getting into the carb. But I don't know if its correctly reaching the cylinders from there. When I crank (esp with choke on) I do see a steady white exhaust coming out of the stack which makes me think something is burning but engine isn't catching. So is there more to check in the fuel system or do you think its time to move elsewhere? Heres a pic of the ignition system. Maybe you can tell me what I'm working with

ignition.jpg

StainlowrAL named it.

A fascinating ignition. No battery or computer required!

Do you have a hand crank? If so ,and after you study safe use ....You can check your rough timing and the "snapping" of your magneto when the timing marks line up.

I am only suggesting here , learn how to set your timing first before diving into your ignition system.
On my 48 with a J4 , Pulling the magneto off the tractor makes working on it much easier. BUT, multiple things can be changed by doing so. Those things ,plus the common sense of confirming timing after working on the ignition makes knowing how to set timing important.

Read up in the manuals section on this forum about how to service your magneto.
A tiny bit of proper grease will be required but you will likely need to clean some things too.

From past habit , when I tear something down I use witness marks on parts that fit together . Cleaning mating edge in a spot can allow a paint pencil to put a mark across the surfaces.
I am not above putting a scratch on some things ,but that would not be a great practice on some one else's stuff...
Also lost a light mark on dirty surface when I cleaned it off....Only remembering what other point (an oil caps centerline) represented that position allowed replacing parts as they were when removed.

It is easy to remove your magneto. Pull dist cap , remove one wire to switch , Coil wire ,two bolts. Easy to get the position of the two lugs on the governor side re positioned (not a good idea if you don't know how to sort out correct position) by turning the piece they are attached to. Those two slots in your governor are at certain positions. Your mag and it's studs need to fit in to them in the same position they were removed. Turning that piece on the back of the magneto turns your rotor. The rotor needs to be pointed at a particular tower on your distributor cap. Also don't want to cause the mag to fire by cranking it wrong/right.
That is just one example of why to be able to keep things in the same positions they were removed....

Also expect a little oil to pour out of a mag. I forgot and got a wet foot. Maybe none will. The correct manual explaining oil in a mag will explain it.

There is a small tab of insulation where your condenser and coil wire are secured. It needs to be where it was before you removed it after you are done.

Easy enough. Just need to know the next step in advance.



By removing your distributor cap (I know ,it sounds odd on a non distributor ignition) you can check condition of points and their gap.
Also your rotors edge where spark jumps to distributor cap towers ,and the towers contacts condition.
Remember ...Study cap position before removing and put witness marks on it if you have any doubt how it goes back on. Drain hole(s) found on something means they go at lowest point. In theory!

Plug wires are in a certain position and touch or don't touch for a reason when installed properly.

Anything we change can change other things. So too much change and affecting things can get hard to back track.
So study process of a service and it's affected system or circuit first. Get it in specs and check it's function.

Again ,it gets much easier the second time.

I changed my J4's coil on top of the mag out in the field. For me to pull the mag (easy way to remove the coil cover and reach the wire connection ,and check points while in there ect. Doubt I could do it any other way) and get it back together and check the timing.... means just about any one can do so.
Just a matter of patience and observing how what goes where. Then setting timing after replacing mag. Removing it changed it and requires resetting it by the mags position by using a certain process.
Yes , I had witness marks for mag position before removing it (l.o.l.) , but that does not mean timing did not need to be checked. Though it was as always set by following instructions of having mag towards engine ,then after positioning timing marks (do you have a hand crank?) then turning mag away from engine till it clicked. (Witness marks were in same location. Did not know if they would be when mag clicked. Would have gone with the instructions for setting timing over my witness marks in that case.)


Points and condenser after cleaning and greasing might be a start for your ignition. Checking rotor and cap too. Condensers are funny critters.
I have been lucky ,but like other parts ,sometimes a new one can be bad. An extra is not bad to have on hand. You know how being prepared can avoid needing to be? Same thing sometimes with ignition parts.

Study how points fit...And know the proper gap and how to set. (Easy too.)

IF you buy a new coil ,seek out an American made one.
I went with a forum sponsor , TM Tractor.
I have a weary coil I replaced that runs when cold but not hot.
Should I suspect a coil failure in time ,I have a coil to use to troubleshoot with now. For a cold engine anyways..

[Matt Kirsch]

I wouldn't even mess with timing as a first step. Changing timing is a last resort, because if you're not familiar with it, you can royally screw things up and dig yourself into an even deeper hole.

First make sure there is a spark. This is easy. Remove the #1 spark plug, stick the wire back on it, and lay the plug against a metal part of the engine. Ignition switch on, tractor in neutral, fuel off, hit the starter. It should spark-spark-spark-spark at every other revolution of the engine. Nice and bright.

[marshall]

First make sure there is a spark. This is easy. Remove the #1 spark plug, stick the wire back on it, and lay the plug against a metal part of the engine. Ignition switch on, tractor in neutral, fuel off, hit the starter. It should spark-spark-spark-spark at every other revolution of the engine. Nice and bright.

Yeah. I don't want to screw up the timing. Plus I have no hand crank so checking spark will be my next move.

Should I do the test with each spark plug or is testing #1 sufficient to determine that a good spark is created throughout?
Also, I read people talking about the quality of the spark being blue, white, etc. Am I just looking for spark, spark, spark or am I looking for certain qualities of the spark if indeed it is sparking?

[Glen]

Hi,
You could check the spark, like Matt said above, and see if there is any.
The spark should be strong, and blue. A yellow spark is weak, and something needs servicing to improve it.
The spark plugs can be removed with the hood on, up under it from the left side. They usually use a 7/8" deep socket, or wrench.
You might need another person to use the starter, while you watch the spark plug from the left side.
You could check the spark on 1 or more spark plugs.
I don't know how long the spark plugs have been used, they could be dirty or fouled, that will make the engine hard to start, or not run, if they are bad enough.

If there is no spark or a weak one, the ignition points could need service, if they haven't been filed or replaced lately. They are a good place to begin, and the points cost less than a new coil.
The points have to be good for the engine to run good.

The points are not hard to replace. Page 30 in the owner's manual I posted above shows the points, and setting the point gap.
You have to remove the plate that holds the rotor, to get to the points. It is held on with 3 screws. Don't turn the engine while the plate is off, you can lose the timing. The plate only fits on one way,
it shows in the manual pic.
You might need to turn the engine slightly with the fan, to make the points open fully, to set the gap.
Notice which way the shaft is turning, so you can turn the shaft that drives the rotor to the same position. The D shaped hole fits onto the shaft only one way.
Below is a listing for new points and condenser at TM Tractor you can look at.

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

I sit next to the engine on a chair, and use a good light, to see in the magneto, and put a large towel on the floor, to catch any small screws I might drop.
You need a short screwdriver with a sort of wide blade, and an 11/32" open end wrench, I think is the size, for the nut that holds the end of the point spring.

[marshall]

We've had non-stop rain for about the last 6 weeks which is making it hard to follow up on this post because the tractor is broken down out in the field.

I ran the tractor with plug #1 pulled and see a white spark (not blue). I'm going to assume that the magneto should be looked at because I've had this tractor since 2013 and used it each summer for mowing (maybe 12-20 hours per summer). The guy who sold it to me was selling off the estate of the farmer who owned it, so I'm going to assume that the points may not have been cleaned or changed in a long time. I've certainly noticed over the past year or two that its been harder to start and seems to have less power when I'm cutting thick grass.

I've got the manual and am following page 30. But the first thing I hit is that I can't get those 3 screws off the distributor body. I've got a short handled screwdriver but as you can see from the photo, those screw heads aren't in great shape. A couple questions:

1. The screws I'm supposed to remove are the OUTER ones (one is shown toward the bottom-right of the picture), not the INNER ones, right? The third is outside this ring and won't release either.

2. I'm seeing no hope of getting these off given the difficult access, munged-up heads, and locked-down tight. What do I do? Can
I take whole magneto off the body and then hope for a better angle to release these or will that mean I've now messed up the timing?
Am assuming that the screws may get destroyed in this process and will have to be replaced (part # ?)

----
Assuming I get past this, the pictures in my manual are somewhat blurry and I'm not really sure I understand from the picture what parts are going to need filing and adjusting. I was kind of hoping when I got a look inside mine, it might be more obvious. I'm wondering, might it be better to just buy that $15 set of point and condensor (http://www.tmtractor.com/new/el/367fp.htm) from TM Tractor and install them with appropriate gap rather than trying to service the ones in there?

[marshall]

Update on this. At the beginning of this project, I put a couple gallons of gas in the tank because I thought that fuel looked low. It didn't start and then I got into the carb which meant turning off the fuel at the valve near the fuel bowl. After servicing the carb and it not starting I moved on to the spark. Just opened the gas tank and find it's EMPTY! Huh? I took the tank off, filled with water (yeah I know, probably dumb). No leaks. I did find an old nozzle from a gas can inside there. I verified that the fuel bowl, gasket, and screen are all good and can seal. Flow of water does go out the fuel line in a nice steady stream. So I'm waiting for this tank to dry out in the sun and then plan to reinstall put in gas.

So... where's the gas going? I'm not seeing it pouring out of the carburetor. Some drips out the bottom of the carb when I'm trying to start it but not at a rate that would drain a gallon or two and only when I'm cranking it. Maybe it's all getting injected into the cylinders and fouling the spark? Regardless, I'm not seeing gas dripping so the whereabouts of a gallon of gas over the course of a month of sitting is mighty puzzling.

My plan is to reconnect everything and hoping to see some life with new spark plugs and flow of gas. The above problem with removing the distributor body remains because I think servicing the points is going to become a necessity at some point and I can't have this thing frozen. So any pointers on that welcome.

[Waif]

No footprints around the tractor to explain the missing fuel? L.o.l... Shut off gas when tractor is not in use. A drip at a fitting adds up quick.
Cap can not fit at tank too. Bungled neck on tank ,or bad seal if original cap. (A free better designed vented new one is available ,one per tractor if stock caps are on them.)

Again. Learn how to set basic timing when reinstalling magneto.
Learn alignment of rotor on the front , and lugs on back of magneto where they engage the governor.
That will allow you to remove the magneto. Then get to those screws. A hollow ground tipped screw driver will gall screws less.

With magneto off you can replace the points and condenser much easier. (Save your old ones for now).
Also if desired you can flush the magneto to clean it , and consider it's lubrication based on climate/temps.

[marshall]

I've got the new cap and close down the valves, but maybe over a month the gallon dripped out somewhere.

Well after putting a gallon in the dry tank and hooking it back up I find the tractor still won't start. So its definitely not a fuel flow issue.
Several times I pulled the drain plug out of the carb to dump out gas. So I saw a spark on #1 and have gas flow to the carb.

So the next place to go is the magneto? Does one automatically believe that the carb is correctly blending air/gas and sending it to the cylinders?
Is there a way to verify that?

[staninlowerAL]

Have you done a compression check? You might have one or more valves stuck.

[Glen]

Hi,
It would probably help if you could get someone to help you tow the Cub to your garage or whatever you have, to work on it.

One of the experts on here said lately, do not remove the magneto, if you don't know how to time it to the engine. It is easy to lose the timing if you remove it from the engine, especially if the impulse mechanism at the drive end is winding, and you remove the magneto, the spring tension will make the magneto drive turn.

The screw head in your pic doesn't look really bad, I would grind a short screwdriver so the blade fits well for the screw head. It needs a sort of large blade that fits the slot fully.
Don't let the screwdriver slip in the slots.
I have removed the plate before, with the magneto in place. It is not hard to do.
Yes, the upper screws are the outer 2.
The inner 2 hold the rotor cover in place.
Yes, you could buy new points, they are better than filing old points, as long as they are made well.

If you want to take off the magneto, it tells how to time a magneto to the engine in the 1950 Cub owner's manual, on page 32. You have to find number 1 cylinder TDC, top dead center.

http://farmallcub.com/rudi_cub/www.clea ... e%2032.jpg