1950 Cub.....Racing Carburetor

Farmall Cub Forum -- Questions and answers to all of your Cub related issues.

Moderator: Team Cub

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.
moretrench1
5+ Years
5+ Years
Posts: 25
Joined: Thu Feb 18, 2010 8:33 pm
Zip Code: 07701

1950 Cub.....Racing Carburetor

Postby moretrench1 » Wed Dec 19, 2012 10:50 am

Hi,
Recently, I sent my Carburetor out for a rebuild. It was in need of a good cleaning and was developing a slow starting problem and issues which seemed to be associated with the float valve.
It was returned and look real good.
After installing, engine fired right up on what seemed liked the first full revolution, but it wouldn't idle down. Prior to the rebuild, this tractor idled perfect.
I disconnected the throttle governor linkage and even after running the idle set screw out and manually closing the throttle, it still seemed to be racing at what I guessed to be well over 1200 RPM.
The other interesting fact was I couldn't kill the engine by closing the choke.

Thanks in advance and any thoughts or comments would be appreciated.

Mark

Eugene
Team Cub Mentor
Team Cub Mentor
501 Club
501 Club
Posts: 15050
Joined: Fri Jul 02, 2004 9:52 pm
Zip Code: 65051
Circle of Safety: Y
Location: Mo. Linn

Re: 1950 Cub.....Racing Carburetor

Postby Eugene » Wed Dec 19, 2012 11:09 am

Check to see if the throttle and choke linkage are on the correct carburetor arms. Easy to get mixed up.
I have an excuse. CRS.

User avatar
Bigdog
Cub Pro
Cub Pro
501 Club
501 Club
Posts: 24066
Joined: Sun Feb 02, 2003 12:50 pm
Zip Code: 43113
Circle of Safety: Y
Location: OH, Circleville

Re: 1950 Cub.....Racing Carburetor

Postby Bigdog » Wed Dec 19, 2012 11:23 am

In addition to what Eugene said - the carb to governor linkage should be re-set every time the carburetor is removed and re-installed. Also make sure the choke arm (if correctly connected) is not turning on the choke shaft.
Bigdog
If you can't fix it with a hammer, you've got an electrical problem.

My wife says I don't listen to her. - - - - - - - - Or something like that!

Image

http://www.cubtug.com

moretrench1
5+ Years
5+ Years
Posts: 25
Joined: Thu Feb 18, 2010 8:33 pm
Zip Code: 07701

Re: 1950 Cub.....Racing Carburetor

Postby moretrench1 » Wed Dec 19, 2012 11:30 am

Thanks for both the suggestions,

I'm sure the choke and throttle arms are correctly connected and will adjust the linkage when I get home on Friday.
But my thoughts regarding the problem are with the carburetor rebuild.
After disconecting both the throttle and choke rods and manually manuevering the throttle plate, I still could not get the tractor to idle down.
Mark

Matt Kirsch
10+ Years
10+ Years
501 Club
501 Club
Posts: 4190
Joined: Tue Jun 08, 2004 3:04 pm
Zip Code: 14559
Circle of Safety: Y
Location: Rochester, NY

Re: 1950 Cub.....Racing Carburetor

Postby Matt Kirsch » Wed Dec 19, 2012 11:35 am

Either the carb rebuild place forgot to put the throttle and choke plates back in the carburetor, or you have a MAJOR air leak around the intake manifold.

User avatar
Rick Prentice
Team Cub Guide
Team Cub Guide
501 Club
501 Club
Posts: 5360
Joined: Mon Nov 01, 2004 7:24 am
Zip Code: 43522
Tractors Owned: 47(circle cub),48(Floyd),49,50demo from GW's collection),51,52(backhoe),53,54,55(Nickles)
Circle of Safety: Y
Location: OH, Grand Rapids (historical town along the Maumee River)

Re: 1950 Cub.....Racing Carburetor

Postby Rick Prentice » Wed Dec 19, 2012 12:30 pm

The first thing I'd check would be the throttle plate. If it isn't seated correctly and not shutting off the air right, it won't idle down all the way. If the idle screw is backed off all the way and the butterfly closes completely, it has to idle down unless the carb guy accidently drilled something he wasn't supposed to :shock: like a bigger hole in the idle curcuit someplace.
Rick
When I told my dad I've been misplacing things and doing stupid stuff----His reply---"It only gets better"

moretrench1
5+ Years
5+ Years
Posts: 25
Joined: Thu Feb 18, 2010 8:33 pm
Zip Code: 07701

Re: 1950 Cub.....Racing Carburetor

Postby moretrench1 » Wed Dec 19, 2012 1:43 pm

Thanks Rick......I guess I'll need to pull off the carb and take a good look inside

sgtbull
5+ Years
5+ Years
Cub Star!!
Cub Star!!
Posts: 452
Joined: Tue Oct 21, 2008 7:50 pm
Zip Code: 62854
Tractors Owned: '36 JD B,
'40 and '46 Farmall H,
'50 Ford 8n '55 Farmall Cub,
'55 JD 70 allfuel,
lots of other toys
Circle of Safety: Y
Location: kinmundy illinois 62854

Re: 1950 Cub.....Racing Carburetor

Postby sgtbull » Thu Dec 20, 2012 8:46 pm

Just out of curiosity, where did you send your carb?
I've never met a tractor I didn't like....but I have found some that were greatly annoying....

CapeCodCubs
5+ Years
5+ Years
501 Club
501 Club
Posts: 2785
Joined: Fri Jan 11, 2008 5:30 pm
Zip Code: 02747
Tractors Owned: .
1948 F Cub Fast hitch
1949 F Cub
1950 F Cub Fast hitch
1965 Loboy Fast hitch

(15) FastHitch implements
tons' of cultivating and planting stuff
C-16 Cub Middlebuster
A33 Cub bean harvested
NOS Planet Jr. planter
172 planter, large combo hopper, 101A fertilzer hopper
Location: MA, Dartmouth

Re: 1950 Cub.....Racing Carburetor

Postby CapeCodCubs » Thu Dec 20, 2012 10:07 pm

Hmmmmm...I thought from the post title you put a Weber, Stromberg or big Solex carb on your Cub!
Image

moretrench1
5+ Years
5+ Years
Posts: 25
Joined: Thu Feb 18, 2010 8:33 pm
Zip Code: 07701

Re: 1950 Cub.....Racing Carburetor

Postby moretrench1 » Wed Dec 26, 2012 3:20 pm

Thanks to ll that commented.
After removal, it seemed the throttle plate had be come jammed. Not only jammed, but bent which may have happened by working the hand throttle lever.
Regardless of how it happened, after removing it to straighten, the throttle plate was larger than than the carburetor throat. I took a file to reshape and reduce the diameter.
after reassembly, all is well and the Cub is patiently awaiting the first Northern NJ snow storm to get in some running time.

Again, thanks...Mark

Bob McCarty
Team Cub Mentor
Team Cub Mentor
501 Club
501 Club
Posts: 7589
Joined: Tue May 25, 2004 8:02 pm
Zip Code: 80501
Tractors Owned: Cubs, MH Pony, Shaw, Allis G, 1934 Silver King, JD LA and LI, Gibson D, David Bradley Tri-Trac
Circle of Safety: Y
Location: CO, Longmont

Re: 1950 Cub.....Racing Carburetor

Postby Bob McCarty » Wed Dec 26, 2012 6:05 pm

Mark, The throttle plate should sit on an angle and the edges are beveled to help it seal when closed. The edge closest to the gas inlet will be further down in the throat if assembled correctly. If you continue to have problems, you may need to replace the plate.

Bob
"We don't need to think more,
we need to think differently."
-Albert Einstein


Return to “Farmall Cub”

Who is online

Users browsing this forum: Garvin Gatewood, Pabst, tnestell and 3 guests