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Spark plug gremlins on my 1949 A

K

Kansas rhody

Member
Got the tractors ready for the local harvest festival today and thought it was time for some fresh plugs. Run champion d23 in my 50, it fired up right away. The A I use Autolite 3116; it would not fire at all. Checked the points, all was well. Was getting good spark out to the plugs via my spark tester. After banging my head against the barn I put in the old plugs, same type, and it fired right up. What are the odds that both plugs were bad out of the box, I checked the gap and they were right at .030. I have another new set, came in a box of 4 and will try the other set when I get the tractor back home. Is it common to get bad plugs or was I just unlucky, first time that has happened to me, thanks
 

Not much to go wrong with plugs. I would confirm the tractor starts. Then remove the plugs and put the two new (no start) plugs back in, give them another try. If no start, then install the originals and confirm it starts. Now install the fresh set (new not used) plugs, if no start then install the original plugs and confirm a start. This is called A - B - A - B testing. Just because the tractor did not start and then did start does not say much about the cause. Maybe it would have started if you took a break for a cup of coffee. A - B testing turns the problem on and turns if off helping to confirm the problem is indeed due to the suspected component.

I would consider it very unusual to get plugs that prevent the engine from starting.
 
I have not encountered bad spark plugs out of the box and agree with Ken. Have found that a spark tester is only good to detect a NO spark situation as they do not indicate the
quality of spark. Some think that flame cleaning a spark plug will restore them to like new condition, it will not.

Start by cleaning all electrical connections from the battery to the spark plug. What condition is your battery cable (the 66 inch one) that runs to the starter? If that cable is the
original you can bet it needs replaced (just been there with my 50) and a couple other of my nearly 70 year old tractors.

Take those no start new plugs and put them in your 50 or another known to start tractor, think you will find it is not the plugs causing the no start. I have had new parts (ignition
parts) that were bad right out of the box. I feel your frustration as I have been trying to get all of my tractors running, it has been challenging to say the least. Good luck.
 
Indiana Ken,

Had to google your A-B-A-B testing, I am not a computer guy at all. Trouble shooting and minor repairs is what makes this hobby interesting for me. Having spent my working
days in a medical laboratory (mostly chemistry) doing quality control and maintenance I have learned that Murphy's Law is always in play and just because a tractor ran good
yesterday or last year does not mean it will run now. The small successes are what keep me interested.
 
Indiana Ken,

Had to google your A-B-A-B testing, I am not a computer guy at all. Trouble shooting and minor repairs is what makes this hobby interesting for me. Having spent my working
days in a medical laboratory (mostly chemistry) doing quality control and maintenance I have learned that Murphy's Law is always in play and just because a tractor ran good
yesterday or last year does not mean it will run now. The small successes are what keep me interested.
 

Brought the tractor back from the harvest festival tonight, started right up 3 times with the old plugs in it, ran great. Will do some troubleshooting tomorrow or Monday and will let you know what I find
 

Did some troubleshooting yesterday, got the tractor running with the old plugs and then started switching plugs around. The champions, d23 fired right out of the box, the autolites 3116s after closer inspection needed the gap fixed, thought I had checked them but they were closer to .050 instead of .030. Once I re gapped the plugs all was well and the old A was running strong. It is always the simple stuff, thanks for the advice
 
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