This site uses cookies to maintain login information on FarmallCub.Com. Click the X in the banner upper right corner to close this notice. For more information on our privacy policy, visit this link:
Privacy Policy

NEW REGISTERED MEMBERS: Be sure to check your SPAM/JUNK folders for the activation email.

Cub starting issues

The Cub Club -- Questions and answers to all of your Cub related issues.
Forum rules
Notice: For sale and wanted posts are not allowed in this forum. Please use our free classifieds or one of our site sponsors for your tractor and parts needs.
Farmlandtractors
5+ Years
5+ Years
Posts: 7
Joined: Fri Jun 19, 2015 5:18 pm
Zip Code: 53010

Cub starting issues

Postby Farmlandtractors » Fri Jun 19, 2015 5:29 pm

I have a 1946 cub runninh on a 6 volt system. I am having trouble with the tractor starting. If you pull the choke when trying to start it gas will pour out the bottom of the carb. It will sound like its going to fire but is difficult to get it going. If you pull it it fires right up and once it's started you can usually get it started again. The carb has been cleaned and the magneto has been timed to the best of my abilities. Once the tractor is running it runs great, I'm just not sure where to start! I don't want to spend money on things I don't need any help would be appreciated.

SPONSOR AD

Sponsor



Sponsor
 

User avatar
challenger
10+ Years
10+ Years
Posts: 1087
Joined: Sun Apr 18, 2010 6:22 am
Zip Code: 21742
Tractors Owned: 1955 F Cub (2)
1952 F Cub
1948 F Cub
2155 JD
216 JD
Circle of Safety: Y
Location: Hagerstown MD

Re: Cub starting issues

Postby challenger » Sat Jun 20, 2015 3:28 am

The first place to start is to perform a compression test on all cylinders. Make sure to blow the debris out of the spark plug depressions around each plug after you loosen but before you remove each plug. Remove all plugs, and with the plugs out crank the engine over with the starter and do a dry test of each cylinder and record the readings. Then squirt some oil in each cylinder and take the wet readings. You hope to find fairly uniform compression readings across all cylinders around 100 psi. Let us know what you come up with.

User avatar
Bus Driver
10+ Years
10+ Years
Posts: 2917
Joined: Sat Feb 11, 2006 5:26 pm
Location: NC

Re: Cub starting issues

Postby Bus Driver » Sat Jun 20, 2015 6:04 am

A different starting procedure would be to turn on the magneto, pull the starter rod with the right hand and if the tractor does not fire quickly, pull the choke rod with the left hand while continuing to actuate the starter. Push in the choke rod as soon as the engine fires. Further experience may indicate a need for longer partial choke application in colder weather.
Luck favors those who are prepared

Eugene
Team Cub Mentor
Team Cub Mentor
Posts: 20336
Joined: Fri Jul 02, 2004 9:52 pm
Zip Code: 65051
Circle of Safety: Y
Location: Mo. Linn

Re: Cub starting issues

Postby Eugene » Sat Jun 20, 2015 7:58 am

Timing light. You can use a 12 volt timing light with a 12 volt power source.

Check the magneto's firing on #1 cylinder at engine cranking speed. Magneto needs to fire at TDC, #1 cylinder at engine cranking speed.

Suspect magneto's timing is off a bit. That's the reason engine starts when tractor is pulled.
I have an excuse. CRS.

Farmlandtractors
5+ Years
5+ Years
Posts: 7
Joined: Fri Jun 19, 2015 5:18 pm
Zip Code: 53010

Re: Cub starting issues

Postby Farmlandtractors » Sat Jun 20, 2015 1:26 pm

I checked the compression a few months ago and it was fine. The tractor is usually started by pulling the starter and pulling the choke, but I'm not sure what you mean about starting the magneto before starting the tractor? I have not used a timing light but I also suspect the timing might be off. I tried to time it to the best of my abilities. Usually after I'm at tdc and I have the magneto on I turn it slightly till it clicks but I'm unable to do it on this tractor because of the top bolt placement.

User avatar
Trent M
Cub Pro
Cub Pro
Posts: 3337
Joined: Wed Aug 09, 2006 6:21 pm
Zip Code: 62859
Circle of Safety: Y
Location: Illinois Southern

Re: Cub starting issues

Postby Trent M » Sat Jun 20, 2015 3:28 pm

I concur with the timing light check. Its common for gas to come out of the leak hole of the carb when trying to start without success. Personally, I found that hard starting was almost always due to timing was off some. And in your case, if it is running fine after a pull-start, I'd bet timing is your issue.
Trent McPeak

Farmlandtractors
5+ Years
5+ Years
Posts: 7
Joined: Fri Jun 19, 2015 5:18 pm
Zip Code: 53010

Re: Cub starting issues

Postby Farmlandtractors » Sat Jun 20, 2015 6:25 pm

As soon as I get a chance I am going to try and time it again and I will let you know how it goes. Because I can't rotate the magneto after ruff timing it to get the impulse Cypher to click over I'm not sure what I'm going to do yet but I'll try and figure it out. Thanks again for all the help!

User avatar
Glen
10+ Years
10+ Years
Posts: 6096
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: Cub starting issues

Postby Glen » Sat Jun 20, 2015 6:57 pm

Hi,
Welcome to the website. You probably need to buy a timing light, and check the timing, like they said in the above posts. It's important that the timing is right so the Cub will start good, and have power when running. A lower priced timing light should be ok, maybe not the cheapest one though, depends on how bright the light is that it makes, you don't want a dim light.
Also, they didn't make Cubs until 1947, you can get your serial number from the plate by where the steering shaft goes into the steering gear, and look at the top of the page here, and you can figure out the year the Cub is. :)

User avatar
Bus Driver
10+ Years
10+ Years
Posts: 2917
Joined: Sat Feb 11, 2006 5:26 pm
Location: NC

Re: Cub starting issues

Postby Bus Driver » Sat Jun 20, 2015 8:07 pm

My comment about the magneto was intended to indicate that one must not forget to set the magneto switch to the RUN position. When Cubs were introduced, virtually all vehicles used separate arrangements for the control of the ignition and of the starter.
Luck favors those who are prepared

Bill E Bob
10+ Years
10+ Years
Posts: 3034
Joined: Wed May 31, 2006 12:09 pm
Zip Code: 74070
Circle of Safety: Y
Location: OK, Skiatook

Re: Cub starting issues

Postby Bill E Bob » Sat Jun 20, 2015 9:57 pm

Bad/weak impulse coupler?

Eugene
Team Cub Mentor
Team Cub Mentor
Posts: 20336
Joined: Fri Jul 02, 2004 9:52 pm
Zip Code: 65051
Circle of Safety: Y
Location: Mo. Linn

Re: Cub starting issues

Postby Eugene » Sun Jun 21, 2015 9:09 am

viewtopic.php?f=1&t=87385&p=695938&hilit=magneto+drive+gear#p695938

Above link, a discussion on magneto and governor timing. There are a number of topics on this site, with photos, on the topic.

Suspect the magneto drive gear is not properly positioned. Probably off one tooth, limiting the magneto's rotation.
I have an excuse. CRS.

Farmlandtractors
5+ Years
5+ Years
Posts: 7
Joined: Fri Jun 19, 2015 5:18 pm
Zip Code: 53010

Re: Cub starting issues

Postby Farmlandtractors » Fri Jun 26, 2015 5:02 pm

So after more research I believe that the top stud that holds the magneto on was not original. This is not allowing me to rotate the mag to have the impulse coupler click over after timing it. Hopefully i will get time this weekend to work on it.

User avatar
John *.?-!.* cub owner
Cub Pro
Cub Pro
Posts: 23701
Joined: Sun Feb 02, 2003 2:09 pm
Zip Code: 63664
Tractors Owned: 47, 48, 49 cub plus Wagner loader & other attachments. 41 Farmall H.
Location: Mo, Potosi

Re: Cub starting issues

Postby John *.?-!.* cub owner » Fri Jun 26, 2015 8:16 pm

I am going to make a guess that you have always had this problem since owning the cub, or since someone has had the governor, front cover off, etc. Loosen the magneto clamps and turn the top all the way toward the engine head. Set the engine to #1 (front) cylinder at top dead center and the mark on pulley lined up with the pointer on block. Turn the magneto away from head until impulse snaps, and tighten clamps. If you cannot turn it far enough to get it to trip, most likely the governor or idler gear is out of time. When a cylinder is at TDC center the drive slots should be in this position. If not one of the gears is out of time.
Image

Since the crank pulley on a cub shipped with a magneto only has one timing mark any timing light you use needs to be one with adjustable timing.
If you are not part of the solution,
you are part of the problem!!!

Farmlandtractors
5+ Years
5+ Years
Posts: 7
Joined: Fri Jun 19, 2015 5:18 pm
Zip Code: 53010

Re: Cub starting issues

Postby Farmlandtractors » Fri Jun 26, 2015 9:53 pm

Thanks for the picture. I was watching a YouTube video everyone was referring me to and it looked like he was rotating the mag on the governor and the top stud you show in your pic wasn't there. I will have to do some work tomorrow and look for clamps. I am fairly mechanically inclined but am new to the older tractors. I'm trying to get all my grandpas tractors running, a 8n, farmall A, and an allis B are as far as I've got still have the cub an H,C, and a ford 860. Lots to do! Thanks for all the help.

Farmlandtractors
5+ Years
5+ Years
Posts: 7
Joined: Fri Jun 19, 2015 5:18 pm
Zip Code: 53010

Re: Cub starting issues

Postby Farmlandtractors » Sat Jun 27, 2015 4:33 pm

[quote="John *.?-!.* "Turn the magneto away from head until impulse snaps, and tighten clamps."
How do you rotate the mag when the top stud is stationary? Mine is the same as the one pictured above. I know some had a bolt with a clamp on the top and I have that on my A and I managed to time that but with this top stud I can't get it to rotate.


Return to “Farmall Cub”

Who is online

Users browsing this forum: dgrapes59, outdoors4evr and 24 guests