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not starting after gasket replace + cleaning of carb

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marshall
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Re: not starting after gasket replace + cleaning of carb

Postby marshall » Sat Apr 13, 2019 3:45 pm

This thread goes back to last fall when I was ready to tow the miscreant cub to the end of my field and put a "for sale" sign on it but I gave it one last chance after it had sat out there for a month in the rain and it, of course, started. So its playing that kind of game. When the season is done and I don't need it anymore, now it's time to show it can run... So I mowed the last bit of field and got it in the barn so that it can let me down in the spring and sure enough, that's what its doing. Exact same issue. It won't start and I've been through the gas system again and just want to verify the next step. I've got a clean fuel bowl/strainer system and verified flow to carb. Carb has been disassembled and cleaned with a new gasket. It's got new spark plugs. I crank and crank but it doesn't catch. I've removed spark plugs and cranked while grounded to metal and see a visible spark but I wouldn't go so far as to say its strong and blue; its small and white at best. I put some new gas in the tank and its not doing any good. So is that about it for the gas system? I checked that the air filter has oil to the right level. Is there any way to know if the carb is doing the right thing with its inputs? There's a pretty steady drip, drip, drip while I'm cranking to try starting it that I start to wonder if the right air/gas mix is getting sent to the cylinders. I have seen the plugs being pretty fouled after all the cranking so am not sure if this is evidence enough that carb is functioning. Lastly, I noticed a little plug just above the carb in the bottom of the manifold . I removed and sprayed some starter fluid in there and tried cranking with plug removed. Oddly, there was a sound almost like it starting but it never did.

I hit some difficulty getting the distributor body off because screw heads are in bad shape and aren't going to be easy to remove. I've ordered the points and condensor from TM. Is replacement of these my next step or are there any other tests to perform before starting to work on the ignition system. Maybe its worth asking now: If I replace the points/condensor and it doesn't start, what's next?

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Glen
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Re: not starting after gasket replace + cleaning of carb

Postby Glen » Sat Apr 13, 2019 7:16 pm

Hi,
Good that you did a spark test.

From what you said, it sounds like the spark is weak, it should be blue when it jumps to somewhere.
Start by replacing the points and condenser. They don't cost a lot. They have to be good for it to run good. If the points haven't been replaced in years, they probably need replacing.

While you have the plate over the points off, check the small insulation piece in the magneto case. People have said that they break, and then it will short there.
Below is a listing for it at TM Tractor. It tells the serial numbers of IH magnetos that it fits, evidently there are some magnetos that it doesn't fit. Check the magneto serial number if you need the insulation. The number usually begins with J4.

http://www.tmtractor.com/new/el/957fp.htm

After those steps, if it doesn't work, the coil probably needs replacing. They get weak and don't put out enough spark. Some of them run when cold, but quit when warm. :)

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Re: not starting after gasket replace + cleaning of carb

Postby offrink » Sat Apr 13, 2019 7:40 pm

How is the air cleaner? Could there be a blockage? Mice or bird get into it? You verify it has fuel, and it has air, then the only thing missing is a spark. Even a badly timed engine will cough and sputter. I had a bad time figuring out a super c. I would clean and file the points, check the coil and all seemed well. I ended up replacing all of it and it starts on the second revolution in -10*f now! Coil and points would be at the top of my list. Since the screws are buggered up and difficult to keep a screwdriver on, could you use a hacksaw or a Dremel tool and cut a new slot for a tight fit?

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Re: not starting after gasket replace + cleaning of carb

Postby Waif » Sat Apr 13, 2019 9:02 pm

Often enough the more you crank on an engine that does not want to start , the more it don't want to start.

Be very sure your plug wires are routed to where they are supposed to be. Or you will likely have fits trying to start it , and start adjusting and replacing and changing more than you want probably. (And yes I've scrambled even labeled wires...)

As always double check your last adjustment and test it before making another adjustment.
I'm learning to recheck sparkplug gaps....As both tractors had issues with plug gaps before I replaced them. (One engine had a gap closed on a plug, the other the gaps were too wide. And that one with gaps too wide did everything but start. Taught me not to keep trying to start it by cranking more. That was wasted time and fuel and battery juice and hand cranking , and cussing.).

After your points and condenser are changed and setting points to specs and saving old parts...Then timing can be rechecked.And cranking the tractor a few seconds to see if she fires...

Note where anything was was before changing it. (Like most changes ,know exactly what changed.) Sometimes a witness mark on dirt or using a paint pen, or making a scratch across two mating surfaces rust similar can save wondering what was where in position. Don't depend on them entirely though ,or one day a mark will disappear...(Done that too.)

If an engine don't want to start and is dripping fuel as well as fouling plugs , shut the gas off. It is not igniting fuel probably.
Over choked can cause that condition too. Be sure choke is doing what you think it is.
One tractor wants just a hint of choke while another wants more but only till it's running ,ect.. That can change with change.
Changing things can change the "sweet spot " in your start up procedure. Even a small change in throttle position can make a difference after a change.

Your spark ,and it's timing are good targets to get fresh and dialed in. Needs doin anyways.
Coil could be checked next. After cleaning wire ends and checking wires for health issues and cranking a few seconds to try the effect of change again..

I've had very poor success in trying to get a flooded Cub to run. Just me probably , but leaving it set a while works best.
Having had a coil give up the ghost , flooding causing a no start is very different. Though the results are the same.

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Re: not starting after gasket replace + cleaning of carb

Postby ntrenn » Sun Apr 14, 2019 5:40 pm

If it won’t hit on starting fluid, you have a basic ignition problem that is limiting spark.

Just because a plug sparks in air, it does not mean there is sufficient spark to run the engine.

Learned that with a Honda Civic engine...good spark with plugs siting on valve cover, but zero spark with a hei spark tester. Fault tree led to coil...and it fired right up with a new coil.

https://shop.advanceautoparts.com/p/otc ... gKVPvD_BwE

(Last one I bought was $15.00)

I’ve also been burned by gas fouled plugs...you cranking and flooding may have fouled the plugs...and you usually can’t tell by looking at them.

Fresh plugs of the autolite 3116 variety will be your friend when you get the new points and condenser in...

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Re: not starting after gasket replace + cleaning of carb

Postby Mrblanche » Mon Apr 15, 2019 9:56 am

Fresh plugs is a good idea. I read through the thread, but I didn't see... Have you tried starting fluid? (Ether) You don't want to use a lot, because it can wash down your cylinder walls, but it will answer the question as to whether you have a fuel problem. You had the carb apart, right? Did it still have its idle tube? This is a common, easily-broken part in the carb, and without it, it likely won't run or start very well. You can buy a new carb on Amazon for about $50, which is what I had to do. Yeah, the guys in here can make great suggestions, and tell you what to check for, and even help you on things that are particular to Cubs, but a little knowledge about older engines in general will help you a lot. They will also tell you you should get an original rebuilt carb. Original is nice, but running is even better.

The fact that your Cub is willing to run in warm weather, and not when it's cooler, points to a carburetor problem to me. Gasoline has to be atomized, and it's hard to do that in cold weather with a bad carb. That's why starting fluid is good for testing for fuel problems. It is already atomized.

Should you choose to buy a carb on Azmazon, when you get it, before you ever put gas in it, take out the float bowl screws. Carefully pull the carb apart, pulling the bowl straight away from the main body. Adjust the float to the proper height. Reassemble it, being careful not to overtighten the screws. Install it on the tractor.

Let me tell you a (sort of) related story. I had a neighbor who had a '57 Chevy she wanted to sell. It had the original 6-cylinder engine in it. It hadn't been run to any extent in 20 years. Her son-in-law tried to get it running, and succeeded in getting it running long enough to move it around in the back yard, but once he shut it off, he couldn't get it restarted. He replaced the gas tank (rusty), rebuilt the carb, and replaced the plugs, wires, points, and condenser. Could not get it running. I bought it for a good price, just to help her out. I found that there was still rust in the gas, because they hadn't changed the filler tube. The gas filter was clogged (because of the rust). The carb was not working well, probably due to the rust, but also due to the worn-out throttle and choke shafts. It took two rebuilds to get that right. Two plug wires were crossed. And he had tried to adjust the points by bending the arm, rather than using the adjuster screw. When I solved those problems, it fired right off. This was a young guy who might never have seen points before. The moral of this is that on an older vehicle, little problems add up to a non-runner, without anything really being seriously wrong.

marshall
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Re: not starting after gasket replace + cleaning of carb

Postby marshall » Sat Apr 20, 2019 2:15 pm

Got the plate off to access the points. When it came off a fair amount of dark oil came dumping out of the chamber. Not sure how that got in there. Maybe someone over greased it. I cleaned up the chamber and removed the old condensor, points, and breaker. They seemed fairly new so maybe person who sold this to me 5 years ago installed new ones. But I put my new ones on anyway. I hit a problem when tightening the nuts/bolt on which the condensor lead and the breaker tie down. Apparently there is a black plastic part in there as well. They form some kind of sandwich. I couldn't even see the black part very well and no replacement for it was included in the points kit. Anyway I tightened too far and this black plastic thing crumbled and fell out of the chamber. I tightened things down the rest of the way and got everything reconnected. I cranked the ignition and am hearing nothing different. Gas drip drip dripping from the carb. Figured I better see if there's a spark. These are new plugs. I pulled number 1 and put it on metal and cranked. Got a small white spark (about the same as before the new points). That's kind of disappointing. Went to get phone to make a video of all this dripping gas and crappy spark. By the time the video is made, the plug aint sparking anymore. I tried hooking a wire from the ground of the battery to the threads of the plug and crank to see no spark.

So now I'm fearing that black plastic part is some kind of insulator and that the magneto is shorting or whatever happens now that this 1 cent part is gone. Anyone know what it is I broke and where I get a replacement? Getting at that sandwich of stuff inside the chamber is not easy. The easiest way to tighten/loosen was by working with the double nuts on the outside of the chamber. But once I get the points back to where they were I have a sense that this isn't going to solve it.

I did try spraying ether up into manifold (thru that plug area at the bottom of the manifold). Now that my spark is gone, I've got to get that fixed before I can go back to looking at that carb (which is kind of what I've been suspecting all along). That thing is dripping gas rapidly when I crank. Yes the plugs get fouled. THey are brand new. I can pull them and wipe them down, but does it really make sense to buy new ones once I get the magneto back to working?

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Dale Finch
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Re: not starting after gasket replace + cleaning of carb

Postby Dale Finch » Sat Apr 20, 2019 4:00 pm

I've replaced that insulator on a couple of my tractors. TM Tractors has it:
http://www.tmtractor.com/new/el/957fp.htm
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Glen
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Re: not starting after gasket replace + cleaning of carb

Postby Glen » Sat Apr 20, 2019 5:34 pm

Hi,
Yes, the black part is an insulator. It has to be good, so the power doesn't short there. Dale posted the link to a new one above. Check the magneto serial number and be sure it fits yours, the number is in the listing. The serial number is stamped in the magneto, they usually begin with J4.
Tighten the nut at the end of the point spring gently, so it doesn't break the insulation.
My post above on this page told about the insulation piece.

The fuel system is probaby good enough for it to run. I would stop working on that.
It is normal for gas to drip out of the carburetor when you crank the engine, and it won't run. It takes some minutes for it to stop dripping, after you stop trying to start it.
It should not drip if it is sitting, and you are not trying to start it.

The spark from the spark plug wires should be blue when it jumps to a ground. The spark needs improving, so it will run. After you replace the insulation piece, and the points, and condenser, and gap the points properly, at .013", if it still has a weak spark, that is not blue, then it probably needs a new coil. It is common for the coil to quit, after years of use, and need replacing.
Below is a listing at TM Tractor for a new magneto coil. If it has the ignition wire plugged into the post on the coil cover, on top of the magneto, it still has the original style coil.

http://www.tmtractor.com/new/el/713fp.htm

There is a rectangular bar through the center of the coil, re use the bar it has, when replacing the coil.

Below are pages from the Cub parts manual showing the magneto, the bar is number 11 in the pic.
You have to remove the cover over the points to replace the coil, to change the small wire on the coil. :)

http://www.farmallcub.info/manuals/cub_ ... 012-22.jpg

http://www.farmallcub.info/manuals/cub_ ... 012-23.jpg

The black oil in the magneto is probably coming from the oil seal leaking, where the magneto is bolted onto the engine. The magneto drive gear has an oil seal.
Below are pics of the drive, and the oil seal.
Attachments
Cub gov gear.jpg
Cub gov seal.jpg
Cub gov seal.jpg (19.86 KiB) Viewed 605 times

marshall
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Re: not starting after gasket replace + cleaning of carb

Postby marshall » Sat Apr 20, 2019 9:59 pm

Glen: I ordered the new insulator. Thanks for those pages from the parts manual. One of the problems I had when tightening that bolt down was I couldn't see very well into that chamber and wasn't sure the order that things went onto that bolt. I've got the lead coming from the condensor, the lead from the coil (the wire heads into the magneto but I am guessing it goes into the coil that resides in there?), and then there's the spring end of the breaker.

So if the spark doesn't improve and I have to replace the coil, does this mean taking the magneto apart and having to re-time the engine or can that be done without re-timing?

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Glen
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Re: not starting after gasket replace + cleaning of carb

Postby Glen » Sun Apr 21, 2019 8:14 pm

Hi,
Yes, the small wire going into the magneto, attached at the point spring end, is from the coil, I think. I don't have a magneto here to look at.
If the coil needs replacing, leave the magneto on the engine, and just remove the cover on top of it, held on with the 2 screws. The coil is under the cover.
Then there are 2 or so screws holding the coil in place.
Inspect and clean the contact post inside the cover that touches on the coil.
Remove the plate over the points, to get to where the small wire connects to.

I use a chair and sit next to the engine, to work on a magneto, or Battery Ignition unit, and you need a good light to see in it too.
I put a large towel on the ground, to catch any screws that might be dropped. :)
Last edited by Glen on Mon Apr 22, 2019 12:11 am, edited 1 time in total.

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Dale Finch
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'56 Cub #194370 "Boris" with Mott Flail mower
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Re: not starting after gasket replace + cleaning of carb

Postby Dale Finch » Sun Apr 21, 2019 8:48 pm

Glen wrote:Hi,
I put a large towel on the ground, to catch any screws that might be dropped. :)

:Dito:
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marshall
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Re: not starting after gasket replace + cleaning of carb

Postby marshall » Thu Apr 25, 2019 1:05 pm

SUCCESS!

I got a replacement insulator and pretty carefully (sheet on the ground, chair, 4X magnifier glasses, flashlight on) put together the stack of wires, insulator, nuts, washers, etc. The new insulator cracked again but only a little chunk of it broke out so I could see that the necessary connections were still isolated from the distributor body. I ran it through spark plug one which was pulled and the engine immediately roared to life despite the missing plug.

So the points were definitely the problem. I think the fact that the distributor had a lot of black oil sloshing around in it definitely messed up the ignition and now that I've cleared out the oil and got clean points in there its behaving nicely. But for how long until that oil comes leaking in again?


Above, Glen answered where that oil that soaked my distributor probably came from. Is there a gasket that creates the oil seal that I ought to be replacing? How far might I have to tear it down to solve the oil leaking? I'm hoping any kind of tear down won't require retiming engine.

Because I broke that insulator I'm figuring I'll probably end up needing to order another from TM and am wondering if I might as well add a new $55 coil at the time so that I don't keep paying these $8 shipping fees every time I need a little thing.
Seems like I'm really trying to avoid the retiming issue. Is there a tool or something I should get so that doing that isn't such an onerous task?

I don't have a hand crank. Not sure if thats necessary for setting timing. Timing light?

Anyway, thanks to all for your help. I feel pretty good about finally solving something other than a gas flow problem.

It's also probably time that I carry out a flush of the oil so that what comes leaking into the distributor at least looks good.


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