9N 6V cutting out when hot

[Mad Farmer]

Have had this tractor a ~35 years. Still original 6V + ground.

Started to have problems with misfiring followed by loss of spark when hot under load. I have replaced the ign switch and the resistor block with parts from here. Problem is still there. Fuel flow to carb drain is fine.

When it starts missing I if I jumper bat to coil side of resistor I can sometimes keep it running a while. I have also tried jumping directly to coil . About the same result. Battery is strong, turns motor over fine even when close to 0 oF. Proper voltage.

When cold the tractor starts up even in cold ( 10 oF) weather and runs fine, idles, has good power. Even when "warmed up" in winter problem seldom happens even when working hard moving snow. It's only when working it hard and it gets hot it starts to cut out. Did it today when plowing w/ a two bottom.

I have not been inside the distributor in a while but the way it runs cold, starts, and has good power makes me think points/timing is O.K. Plugs are new NGKs


I plan on pulling the distributor soon and have an old NOS CNH tune up kit I plan to install (good quality points, cap, rotor etc....). If that don't solve the problem I'm thinking the coil gets weak when it gets hot. Any other ides what could cause these symptoms?

Concerning coils, they seem to vary quite a bit in price, and I wonder about relative quality? The site here is ~$25, NAPA has Balkamp and Echlin, at ~$50 and ~$95 , respectively. Is the Echlin coil that much better to justify the price?

Thanks for suggestions/insight.

P.S. do you guys pull the genny so you can get at the distributor more easily?

 

[HCooke]

If you have run a jumper wire directly from the battery to the top of the coil with no improvement then the problem lies in the coil/distributor.

"do you guys pull the genny so you can get at the distributor more easily?"

No, I don't. Some advocate loosening the belt, but I don't do that either.

 

[Mad Farmer]

(quoted from post at 05:25:59 05/15/20) If you have run a jumper wire directly from the battery to the top of the coil with no improvement then the problem lies in the coil/distributor.

"do you guys pull the genny so you can get at the distributor more easily?"

No, I don't. Some advocate loosening the belt, but I don't do that either.

Any thoughts on 6V coil quality?

 

[JMOR]

(quoted from post at 09:31:57 05/15/20)

(quoted from post at 05:25:59 05/15/20) If you have run a jumper wire directly from the battery to the top of the coil with no improvement then the problem lies in the coil/distributor.

"do you guys pull the genny so you can get at the distributor more easily?"

No, I don't. Some advocate loosening the belt, but I don't do that either.

Any thoughts on 6V coil quality?

oints wear will alter dwell (coil charging time) resulting in reduced energy and wear can also result in a reduced gap which causes energy loss in opening arc to increase. Condenser. Something is causing a weakened output and the natural coil energy loss that occurs with heat is now falling below what engine needs to run right. So, as you say if new poits/adjustment, condenser doesn't fix it, you look to coil.

 

[Bob - MI]

Makes me think it's the coil.

I bought one for my 2N years ago and it wasn't from Napa. Ask the Napa guys what they think about the price difference.

I would be tempted to go with the $25.00 version from this site. I would bet that they have sold a LOT of those over the years and if the quality wasn't there they would switch suppliers.

 

[Mad Farmer]

I've thought about that too JMOR. But usually when points get that bad timing is so far off it won't start/run well.

Tractor still starts great and brush hogs/plow a 2-bottom fine, until hot.

I'm crossing my fingers until I get inside dist.

I'm hoping I won't have to, but again quality of coils available today?

NAPA Balkamp vs Echlin is 1 vs 3 year warranty. But latter costs twice as much.

I have read up on doing distributor in the past. Using a modified brass thumb screw for top screw, and plastic push in nylon insulator to replace original, check bushings/advance weights......

I have downloaded Kevin LaRue's tutorial as a hard copy on doing points, from myfordtractors. Lots of good info there

 

[JMOR]

Quality of coils for front mount.....I really can't say, but years ago after bad experience with new one, I cut it open, removed guts and wired case such as to be able to use a standard later round can coil and all has been well since, other than oxidized points when tractor has not been started for several months.

 

[Mad Farmer]

I tried to start the N this morning, no go. Plugs sooty black. Took a bit of steel wool to them, and the N fired up in 2 seconds.

I'll try to finish plowing garden before it gets hot. Drier now, but been wet cold spring here and storms this evening.

I'll update when I pull dist.

Experiences, good or bad, with replacement front mount 6V coils will be appreciated meantime.

Anybody pull/use one from a scrapper N?

Thanks for the help.

 

[lha]

I've been running the same coil for about 12 years or so,but have heard of some that didn't last long. Wiring and condition of ballast resistor might affect longevity.

 

[Mad Farmer]

(quoted from post at 22:51:00 05/15/20) I've been running the same coil for about 12 years or so,but have heard of some that didn't last long. Wiring and condition of ballast resistor might affect longevity.

Which coil? Brand.

 

[Mad Farmer]

(quoted from post at 05:25:59 05/15/20) If you have run a jumper wire directly from the battery to the top of the coil with no improvement then the problem lies in the coil/distributor.

"do you guys pull the genny so you can get at the distributor more easily?"

No, I don't. Some advocate loosening the belt, but I don't do that either.

I saw the thread with the Ns you sold, a nice collection. I see why you don't need to pull genny on those to service dist.

My 9N has a good amount of grime, I think I'll be pulling the genny and giving the motor a scrubbing before I pull the dist.

 

[lha]

(quoted from post at 05:51:00 05/16/20) I've been running the same coil for about 12 years or so,but have heard of some that didn't last long. Wiring and condition of ballast resistor might affect longevity.

believe I got it from Tractor supply,but not sure. Luck plays a part in this,as much as anything else. I must have found the one in a hundred that's right.