1941 9N odd problem.

old

Well-known Member
So was working in this tractor today. Put in new points from CNH and have spark but what is odd seems the spark will only spark as you let up on the starter button. It will not start either. Pull it 10 feet and it fires right up but does not run well. #2 and #4 plugs are wet when you try to start it with the starter and #3 is black and sooty. Opened up the carb that I had rebuild 2 years ago and was clean as could be. Told the guy to try a new set of plugs since these are 2 or 3 years old and let me know.
Any ideas as to why the odd spark problem. 12 volt conversion by the way. Compression is a tad low also. Been sitting about a year with out running. Did put a table spoon of ATF in each cylinder to help that
 
My money is on a bad connection drawing all the "juice"
away from the ignition while cranking the engine.
Unless someone has rigged some kind of by-pass circuit.
Have you measured voltage at the top of the coil while
cranking to see if it's too low?
 
You say,(Pull it 10 feet and it fires right up but does not run well. #2 and #4 plugs are wet)
Check the firing order,it may be 0ff.1-2-4-3 Try hot wire.
 
I'm not sure but I think my 8n was doing that same thing last night today I changed the ignition resister and it fired right up. I haven't proven that it was the resistor , but it's an easy check. What made me think that was it , I had a 59 ford that did that and it was the resistor.
 
I did wire around the ballast resister and that did not help any. Did not have a meter with me today. Did have a test light but that was no help other then to conform that the points where bad. Think could be the plugs being old/bad and or low compression since the #3 cylinder was at around 35PSI dry and cold but #4 was at 90 dry and cold
 
"only spark as you let up on the starter button"

I don't see how this statement fits with low compression.
Starting when pulled fits with low compression though.
Sounds like more than one issue going on there.
 
As far as I know the cap and wires have not been moved or other wise messed with since I worked on it 2 years ago. Compression has me thinking it has maybe sticking rings or other such thing. Thought about a hot wire after I had left. I did wire around the ballast resister for a hotter spark but that did not help
 
#4 had 90PSI and #3 had 35 or so did not check the others due to being hard to get my gauge hooked up. The odd spark has me thinking what the heck other then maybe the starter getting weal and drawing to many amps
 

Weeeeell young fella I am with Royse too. I have seen this a few times and it comes up here every now and then too.
 

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