NAA problems

[MSUSparty]

I wasn't getting a charge out of the generator on my NAA and the battery was bad. So, I thought it would be a good time to do a 12V conversion, since I had to replace the battery and address the charging issue anyways. I did the conversion this past winter and the tractor fired right up in the shop and seemed to run good, though I only ran it briefly (indoors). Last week I pulled it out and started using it and it ran great!... for 2 hours. Then it began to sputter... then backfire... then wouldn't run/start at all. I cleaned the points and plugs and checked the gaps. It started but sputters a lot. I've double checked all the connections, thinking that maybe I failed to tighten something down and it loosened up. It seems to have good spark at the distributor. Although I am definitely not a mechanic, I have been using this tractor for 30+ years and feel fairly comfortable adjusting the points, so I don't feel like that is the problem.

I find it strange that it ran so well for a couple hours, then went from running well to not running at all so quickly.

Thoughts/ideas? Did I do something wrong on the conversion?

Thanks

 

[pomester]

I wasn't getting a charge out of the generator on my NAA and the battery was bad. So, I thought it would be a good time to do a 12V conversion, since I had to replace the battery and address the charging issue anyways. I did the conversion this past winter and the tractor fired right up in the shop and seemed to run good, though I only ran it briefly (indoors). Last week I pulled it out and started using it and it ran great!... for 2 hours. Then it began to sputter... then backfire... then wouldn't run/start at all. I cleaned the points and plugs and checked the gaps. It started but sputters a lot. I've double checked all the connections, thinking that maybe I failed to tighten something down and it loosened up. It seems to have good spark at the distributor. Although I am definitely not a mechanic, I have been using this tractor for 30+ years and feel fairly comfortable adjusting the points, so I don't feel like that is the problem.

I find it strange that it ran so well for a couple hours, then went from running well to not running at all so quickly.

Thoughts/ideas? Did I do something wrong on the conversion?

Thanks

Did you put a resister in the line to the coil? Or change the coil to a 12v unit? Possibly the coil is getting hot running on 12v. Will it start and run after cooling down for an hour to two?

 

[MSUSparty]

Did you put a resister in the line to the coil? Or change the coil to a 12v unit? Possibly the coil is getting hot running on 12v. Will it start and run after cooling down for an hour to two?

I changed the coil to a 12v coil with internal resister. No, it cooled down overnight but did not run any better the next day.

 

[Mad Farmer]

Check fuel at carb drain plug to rule out that. Also look at fuel that comes out, no water?

If OK, go back to electric.

Use multimeter with ohms and volts to check connections quickly for continuity and/or voltage. Make sure points are really clean and check gap/dwell and timing.

 

[steve in ok]

My 850 did the same thing. check the copper strip inside the distributor. Mine was cracked and made it act up about the same way you describe.

 

[Jeff Hamilton]

Hi Sparty - GO GREEN! I have had similar issues with my 860 and 8N. In those cases I was victim of cheesy point sets. They look fine but not sure why, they're all show and no go. I have had luck with either the Standard Ignition (Blue Streak) FD-8081, or NAPA CS753.

 

[MSUSparty]

Thanks for the replies everyone. Mad Farmers suggestions about checking the fuel got me thinking. I fueled up shortly before I started having problems, so maybe there was water in the fuel or something. That will be the first thing I check when I have time to work on it. I'm hoping tomorrow. I'll keep you updated.

 

[Btzj02]

It would be interesting to know new battery voltage and battery voltage when it stopped running. To add to what Jeff said in post #6, due to poor quality condensers, I have learned when replacing points and condenser on a running tractor I first only replace the points. After points replacement and proof the tractor runs good I then replace the condenser. It is a little more work but it limits my trouble shooting to one thing at a time.

 

[MSUSparty]

Update:

I checked fuel at drain plug of carburetor and it was flowing fine. I ended up draining the fuel and putting new fuel in just to eliminate that as a problem. That was not the problem.

I have not changed the points recently. I cleaned the points and double checked the gap. I inspected it and I don't see any obvious problems. I have ordered a couple sets of Standard FD-8081 per Jeff's suggestion. Even if that's not the problem, it doesn't hurt to have a spare on hand.

I tested the ignition coil (hopefully I tested it correctly, watched YouTube video... used multimeter to check ohms between terminals). Its reading 0 ohms between the pos and neg posts. I'm assuming that's not right. Could that be my problem?

 

[old]

Update:

I checked fuel at drain plug of carburetor and it was flowing fine. I ended up draining the fuel and putting new fuel in just to eliminate that as a problem. That was not the problem.

I have not changed the points recently. I cleaned the points and double checked the gap. I inspected it and I don't see any obvious problems. I have ordered a couple sets of Standard FD-8081 per Jeff's suggestion. Even if that's not the problem, it doesn't hurt to have a spare on hand.

I tested the ignition coil (hopefully I tested it correctly, watched YouTube video... used multimeter to check ohms between terminals). Its reading 0 ohms between the pos and neg posts. I'm assuming that's not right. Could that be my problem?

Do you have a good blue/white spark at the center wire of the distributor cap that will jump a 1/4 inch gap or more and also at all the plug wires?? I take an old spark plug and gap it to as close to a 1/4 inch as I can to test for spark