Dimishing spark

Luu said:
I rented a compression gage from a local auto parts store and got the following results. #1 80 psi, #2 70 psi, #3 75 psi, #4 79 psi. I also bought a 6/12 coil and hooked that up with a switch to the battery per advice. The distributor (and plugs) seems to be getting a stronger more consistent spark with the external coil in place. While it isn't ideal, my main goal is to just to see if I can get it to start. After that I will go through other things.
Do we think the compression is enough?

I had primed the oil pump before I started all this about 2 months ago. I gave the passage a couple more squirts of oil and it didn't take but 2. So I feel the pump is working. That and I didn't tighten the cap tight enough and oil was seeping out as I was turing over the engine.
@cubguy's dad - I'm not sure how to find the information you're talking about.
@Farmallsodbuster - The old point looked pretty good other than maybe a little less of the contact pad.

I was running out of time so I only tried a couple times to start it but with a couple shots of starting fluid there was no fire. I'm going to double check the timing and look into a spark tester if I can find the information.
Thanks again for everyone's help so far.
Click to expand...
This comment by poster Luu is from last Sunday and indicates to me that he now has an external coil in use rather than the mag coil. I'm confused now by what seems to be comments that probably don't apply to this situation that I really don't know what is going on. :unsure: JMHO Stan
 
I am sorry if this has caused confusion or if I am calling something by the incorrect name. I am new to working on tractors and I may not be explaining everything correctly.

So to summarize, I have a J4 magneto (original set up) that as suggested in the trouble shooting process, I removed the internal coil and installed an external coil per advice of @staninlowerAL and connected to the 6 v battery with a switch. The external coil was a cheaper (temporary) choice and I could get one down the road at a Tractor supply store. One of the latest posts by @cubguy's dad explained a step by step diagnosis process I should follow to narrow down the weak spark issue I still have at the plugs. This was very helpful and I appreciate that.

Now, after following @cubguy's dad process. I have narrowed it down to the last step where I connect the external coil back up to the "distributor" cap and test the spark at the plugs. The plug I tested, #4, had weak spark. If I understand the process then, it could be the cap, or rotor, or plug wire. All of these are new and have continuity at the connections. Visually they look perfect. I'm going to look at the other plug wires and swap them around if I find that one works better than the other. I'm really hoping not to throw some more parts at this if they aren't bad.

Thank you and sorry that this post is getting so long.
Kris
 
So do you have a 6v coil to go with the 6v battery? Earlier you posted a 6/12 volt coil. Is there a resistor in the circuit to the mag not functioning as a distributor? Stan
 
At the risk of showing ignorance I will say that I've not seen or heard of a coil that was ID'ed as 6/12 volts. Maybe someone else will comment. Can you measure the battery voltage input and output to the points? And do you have it installed for pos or neg ground. My thought is if you're using a 6v battery that somehow you are not getting the correct voltage to the points with this coil. You should have about 4.3-4.5 volts (+ or - a little) input to the points. I see that the spec/description says that if you are using it on a 12v system, an external resistor is required so I interpret that to mean the coil has no internal resistor. Stan
 
UPDATE: My area of Wisconsin got hit with a tornado including my property. We are ok but will likely be without power for another week. My 200 year old trees were toppled as well as damage to a couple buildings. I've been working 14 hours a day since Monday trying to clear trees so crews can come in. I just don't have the equipment to cut and move things around.

Anyway, I won't be able to work on my little Cub for a while . I appreciate the advice I've gotten so far and look forward to getting back to normal sometime.
Thank you and God bless.
Kris
 
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