Replacement Coil

[super99]

My Oliver 1550 has started missing and looses power going up a hill or under a load. The coil is not hot to the touch when running. A guy on a ride said his 1650 did that and he replaced the coil and that fixed it. I bought a coil at Napa and was going to put it on but the sticker says if the alternator puts out more than 13.8 volts the warranty is void unless I add a resistor. I checked it and it puts out 14.2 for a little bit after starting and then drops below 13.8 running. Can I use it as is or do I have to get a resistor to add to it?

 

[Janicholson]

My Oliver 1550 has started missing and looses power going up a hill or under a load. The coil is not hot to the touch when running. A guy on a ride said his 1650 did that and he replaced the coil and that fixed it. I bought a coil at Napa and was going to put it on but the sticker says if the alternator puts out more than 13.8 volts the warranty is void unless I add a resistor. I checked it and it puts out 14.2 for a little bit after starting and then drops below 13.8 running. Can I use it as is or do I have to get a resistor to add to it?View attachment 76310

Run it. There is no real issue. When it is down at 13.8, take a photo of the volt meter (with time stamp) to show the run charging is correct. Jim

 

[super99]

Run it. There is no real issue. When it is down at 13.8, take a photo of the volt meter (with time stamp) to show the run charging is correct. Jim

I should have added that I’m not so concerned about the warranty , just wanted to make sure too many volts wouldn’t hurt the coil. Thanks

 

[Mike(NEOhio)]

There should be a resistor wire to the coil in the harness. It's teed into a wire off the starter relay. When the relay is triggered it sends full voltage to the coil for starting. Resistor wire feeds the coil when running. That wire is gray on mine and 3 or 4 feet long, folded into the harness.

 

[Geo-TH,In]

My Oliver 1550 has started missing and looses power going up a hill or under a load. The coil is not hot to the touch when running. A guy on a ride said his 1650 did that and he replaced the coil and that fixed it. I bought a coil at Napa and was going to put it on but the sticker says if the alternator puts out more than 13.8 volts the warranty is void unless I add a resistor. I checked it and it puts out 14.2 for a little bit after starting and then drops below 13.8 running. Can I use it as is or do I have to get a resistor to add to it?View attachment 76310

Most coils draw about 4 amps. To drop one volt, you need 0.25 ohms.
2 volts the resistor needs to be 0.50 ohms.

Use a 12v battery and measure the current.

Good luck finding a resistor small enough to drop one or two volts.

 

[John T]

Good mornin Super 99, good questions here are my thoughts.

1) The tractors missing may or may NOT be due to the coil ?? More often its the points are burned, pitted corroded or mis gapped or there's a
plug, plug wire, condensor or distributor or cap n rotor problem, I usually check those FIRST before suspecting the coil IM NOT SAYING THE
COIL ISNT THE PROBLEM ...it may be ???????? Ive seen a bad condensor cause ignition problems after the tractor warms up or under a heavy
load. Typically the coil current is 4 or less amps to prevent premature burning of the points, so the resistance of the coil plus any ballast on a
12 volt system would be 12/4 or 3 ohms.

2) Do you have an alternator or a Generator ?? (sounds like alternator just asking) I ask because an original Generator may not be raising battery
voltage quite as high as an alternator, subject to voltage regulation and RPM etc.

3) The coil is powered by the Battery, not direct off a generator or alternator, and even if it has an alternator subject to RPM and the battery, AS
YOU POSTED the battery voltage may not stay at 14.2 very long before it settles in and stabilizes at 13+ NOTE again voltage regulation, RPM
and the condition of the battery determines the battery voltage.

4) DISCLAIMER I dont know the coil or its design or specs etc etc and dont want to offer bad advise that may void a warranty HOWEVER that
being said and noted ITS MY BEST PURE GUESS ABSENT ANY SPECS that coil will work fine. NOTE I wonder what that
coils LV Primary resistance is ?????????? If it's a lot under 3 Ohms Im more inclined to think IT DOES NEED SOME ? BALLAST

5) A typical old fashion ignition ballast resistor for use of a 6 volt coil on a 12 volt tractor is in the 1.5 to under 2 ohms range THAT WOULD
NOT be for use in your case. If your charging system and battery is keeping the battery over 13.8 volts and you wanted to use a voltage
dropping ballast to reduce it slightly THAT WOULD REQUIRE A MUCH LOWER RESISTANCE POWER RESISTOR the value of which requires
calculation. Typical LV Primary resistance of a 12 Volt Coil is around 3 Ohms WHAT IS THE RESISTANCE OF THAT COIL ????????????

SUMMARY AND SHORT ANSWER: CHECK THE COILS RESISTANCE if a lot under 3 Ohms (say 1.5 to 2+) my answer and best guess will
change !!!! After that, I would FIRST make sure the problem isn't the points or condensor, plug or plug wire, cap or rotor
etc................I GUESS the coil would be fine but cant say for sure absent more information, its YOUR decision. Hopefully other fine gents
who have had experience with THAT COIL can offer their thoughts and opinions ?? Hope so its fun to learn from others !!!!!!!!!!! I look forward to
what others have to say

Best wishes to everyone here

PS if you now have a 6 volt coil which is used on some 12 volt tractors, those have a 12/6 voltage dropping ballast resistor and ballast by pass when cranking. Iffff that’s the case you need a 6 volt coil orrrr use that coil without the ballast It’s a whole different story if that’s what you have so post back and let me know. My answer above is based on you have an original 12 volt coil

John T

 

[used red MN]

There should be a resistor wire to the coil in the harness. It's teed into a wire off the starter relay. When the relay is triggered it sends full voltage to the coil for starting. Resistor wire feeds the coil when running. That wire is gray on mine and 3 or 4 feet long, folded into the harness.

If Mike..Ohio is an Oliver guy and knows what he is talking about which I think he does, that is the wrong coil for your tractor you need a 6 volt coil that is approx. 1.5 ohms on primary circuit. I should say if your wiring is stock as Mike laid out. A 12 volt coil fed through a resistor wire feed will make your spark weak.

 

[JOCCO]

I am in the camp if the tractor is running good except on hills it is not the coil. Also there is a coil tester I have a snap on one. It removes all doubt and can even heat the coil for hot testing.. Best investment I ever made on coils.

 

[miangus]

If Mike..Ohio is an Oliver guy and knows what he is talking about which I think he does, that is the wrong coil for your tractor you need a 6 volt coil that is approx. 1.5 ohms on primary circuit. I should say if your wiring is stock as Mike laid out. A 12 volt coil fed through a resistor wire feed will make your spark weak.

This is good advice. I have seen numerous occasions on this site where improper modification of the Delco bypass system has turned a good starting tractor into a problem child. Hard starting or burning points.

 

[wh]

My Oliver 1550 has started missing and looses power going up a hill or under a load. The coil is not hot to the touch when running. A guy on a ride said his 1650 did that and he replaced the coil and that fixed it. I bought a coil at Napa and was going to put it on but the sticker says if the alternator puts out more than 13.8 volts the warranty is void unless I add a resistor. I checked it and it puts out 14.2 for a little bit after starting and then drops below 13.8 running. Can I use it as is or do I have to get a resistor to add to it?View attachment 76310

Have has same symptoms in farmall h. Bo power under load and rough running. New spark plugs fixed it. Went from nearly new champions to autolite.

 

[JMOR]

super99 said at the beginning, "I checked it and it puts out 14.2 for a little bit after starting and then drops below 13.8" So why advise him that he needs a 6 volt coil? Do people read the questions or just simply blindly respond?

 

[John T]

If Mike..Ohio is an Oliver guy and knows what he is talking about which I think he does, that is the wrong coil for your tractor you need a 6 volt coil that is approx. 1.5 ohms on primary circuit. I should say if your wiring is stock as Mike laid out. A 12 volt coil fed through a resistor wire feed will make your spark weak.

Exactly. If it’s a 6 volt coil on a 12 volt tractor that uses a ballast resistor that 12 volt coil he pictured will yield a low energy spark snd for sure with that ballast there won’t be any chance of excess coil voltage lol I question if the coil is even the problem but he needs a 6 volt coil if original or use that new 12 volt if he ditches the ballast.

Nice sparky chatting with you

John T

 

[John T]

super99 said at the beginning, "I checked it and it puts out 14.2 for a little bit after starting and then drops below 13.8" So why advise him that he needs a 6 volt coil? Do people read the questions or just simply blindly respond?

The only reason he needs a 6 volt coil is if it’s one of those 12 volt tractors that uses a 6 volt coil plus an external ballast and ballast by pass when cranking feature. If it’s a straight 12 volt tractor coil then he obviously needs a 12 volt coil only iffff the coil is the problem which I doubt. We need to know if it’s a 12 volt coil orrrr a 6 volt with ballast. I tried to cover both in my answer above with the last PS.

John T

 

[used red MN]

super99 said at the beginning, "I checked it and it puts out 14.2 for a little bit after starting and then drops below 13.8" So why advise him that he needs a 6 volt coil? Do people read the questions or just simply blindly respond?

JMOR, Refer to reply 4 and reply 7. I guess you could just blindly assume S99 knows his tractor like the back of his hand and assume he has it wired it different than stock. Then not mention a thing and let him trudge along and wonder later why his tractor is not starting and performing as it once did. Is this the real problem with his tractor, in my opinion likely not. But he already has the coil in hand.

 

[JMOR]

I guess you could just blindly assume S99 knows his tractor like the back of his hand..

yes

 

[used red MN]

I guess you could just blindly assume S99 knows his tractor like the back of his hand..

yes

Well I don’t know him like he is my next neighbor and best tractor guru. I actually believe I have seen him post that electrical is not his strong suit. So I give the expanded version with details the best I know how. I suppose you can have your way and I’ll choose mine and agree to disagree.

 

[JMOR]

Well I don’t know him like he is my next neighbor and best tractor guru. I actually believe I have seen him post that electrical is not his strong suit. So I give the expanded version with details the best I know how. I suppose you can have your way and I’ll choose mine and agree to disagree.

No need to disagree. You did fine. Not sure there is ever too much information.

 

[super99]

It has a 12 volt coil with built in resistor on it now, that way when I got it. Wiring harness was new put on by previous owner. New plugs, wires and cap 200 hours ago. I looked at points and they look new, wondering about the condenser, I have a new one I could put in the next time it rains. Inside of the cap looks good. If had been running great, idle to full throttle with no hesitation and then started sputtering when under a load from 1700 to 2000 rpm and then smooth out to wide open, steadily got worse to sputtering anytime I push throttle all the way open or under a load. Last resort, I have another 1550 that I could switch distributors to see if it changes.

 

[Janicholson]

It has a 12 volt coil with built in resistor on it now, that way when I got it. Wiring harness was new put on by previous owner. New plugs, wires and cap 200 hours ago. I looked at points and they look new, wondering about the condenser, I have a new one I could put in the next time it rains. Inside of the cap looks good. If had been running great, idle to full throttle with no hesitation and then started sputtering when under a load from 1700 to 2000 rpm and then smooth out to wide open, steadily got worse to sputtering anytime I push throttle all the way open or under a load. Last resort, I have another 1550 that I could switch distributors to see if it changes.

If the distributor cam shaft bushing is worn, it will act like that. If you can move that shaft Up Bown Toward engine or away it is in need of a rebuild. Jim

 

[used red MN]

Is this one of them Olivers with a vacuum advance? I know in the automotive world the pivots in the points mounting plates could get worn and then the points gap would not be kept the stable through the advance stroke. Ford Autolite distributors were bad for that.