Warm Starting Difficulty--Weak Spark Plugs

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.
Ironlegs
Cub Star
Cub Star
Posts: 101
Joined: Tue Aug 21, 2012 10:21 am
Zip Code: 16426
Tractors Owned: 1951 Farmall Super A
1958 Farmall Cub
Circle of Safety: Y
Location: McKean PA

Warm Starting Difficulty--Weak Spark Plugs

Postby Ironlegs » Mon Apr 29, 2013 8:34 am

My 1958 Farmall Cub would not re-start well when warm. I bought the unit about two years ago and had finished a whole tractor restoration this past winter. The Cub would fire-up fine when cold but progressively got harder to re-start when warm. My restoration had included just about every system and component...except the spark plugs.

The Autolite 3116's that came with the tractor looked okay. I cleaned and re-gapped them and they performed when the tractor arrived. Only after checking and re-checking the fuel system, carburetor, governor, distributor, timing, compression and valves (tappet gap) did I give the spark plugs some thought. I replaced the original plugs with Champion D21's which are understood to be "hotter" spark plugs. The hot start problem was found and eliminated!

So, to help others who may have tractors with the same symptoms, I offer this post. I have used Autolite 368's with no issues and have years of trouble-free service from Autolite 3116's. Right now, both of my tractors have Champion D21's and the performance is great.
Ironlegs John

User avatar
John *.?-!.* cub owner
Team Cub Guide
Team Cub Guide
501 Club
501 Club
Posts: 21532
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: Warm Starting Difficulty--Weak Spark Plugs

Postby John *.?-!.* cub owner » Mon Apr 29, 2013 9:45 pm

I have run into a similar problem, and changed plugs a couple times till they failed to solve the problem. I finally figured out it was a coil going bad and the spark was getting weaker all the time.
If you are not part of the solution,
you are part of the problem!!!

User avatar
Rick Spivey
Cub Pro
Cub Pro
501 Club
501 Club
Posts: 1934
Joined: Sun Jul 01, 2007 10:07 pm
Zip Code: 29681
Circle of Safety: Y
Location: SC, Simpsonville 29681

Re: Warm Starting Difficulty--Weak Spark Plugs

Postby Rick Spivey » Tue Apr 30, 2013 5:06 am

I also suspect you are seeing the start of a coil problem. Keep an eye on it, and replace the coil before you go through too many sets of plugs.
Rick Spivey
'52 Cub ("Great Personality") 148xxx
'48 Cub with FH ("Gunny Cub") 38xxx
'57 Lambretta (a slow work in progress)
'74 Triumph TR6 (Mama's toy)


Return to “Farmall Cub”

Who is online

Users browsing this forum: 1951newowner and 7 guests