| The presence of a gasket would be more likely to decrease an already weak spark because it would move the cap out from the rotor. But that's a stretch. Stick w/ the likely causes of a weak spark on a frontmount: 1. The insulator under the brass concave head screw. 2. The insulator at the end of the points where the copper strip attaches. 3. The copper strip is broken or grounded to the plate. 4. The condenser wire grounding. 5. The pigtail/tab not making contact. 6. Incorrect positioning of the spring clip on the plate causing the pigtail to ground. 7. Incorrect seating of the coil on the distributor due to a loose bail or no gasket; the coil must not move at all. 8. Water/moisture inside the cap due to gasket failure or the absence of a gasket. 9. Dirty/corroded/incorrectly gapped points 10. Burned rotor, cracked/carbon tracked cap. Unless the coil is cracked or shows a dead short, chances are it's fine; square coils rarely fail cold. Pull the distributor & do a continuity check. The front distributor was designed to come off of the tractor to replace/adjust the points. Remove the wire on the coil, remove the coil bail, remove the distributor cap & take the two bolts off. The base of the distributor has an offset tang & can only go back one way unless you really force it on. First, make sure your meter/light works (don't ask....) Next, dress the points by running a piece of card stock or brown paper bag through them. New points sometimes have an anti-corrosive dielectric coating on them & old points can corrode or pick up grease from a dirty feeler gauge or excessive cam lubricant. Then, check the gap at .015 on all 4 lobes. (If you are going to set the timing, do it now. If you don't know how to do that, ask) Now, follow these steps: 1. Coil off, cap off, points open. One probe on the brass screw & the other on both sides of the open points. On the side closest to the cam, you should have continuity. Not on the other side! If you do, you will also have continuity everywhere because the points are grounded. 2. Coil off, cap off, points open. One probe on the brass screw & the other anywhere on the body of the distributor. You should have no continuity! Now, rotate the tang on the distributor....as the points open & close, you have continuity (closed) and lose it when they open. 3. Coil on, cap off, points open. One probe on the lead on the top of the coil, the other on the cam side of the open points. You should have continuity! 4. Coil on, cap off, points open. One probe on the lead on the top of the coil, the other anywhere on the body of the distributor. You should have no continuity!
At this point, I just put the distributor, coil & cap all back on the tractor as a unit (it’s easier to do this from the left side). The reason I do this is because it is real easy to get the cap or coil mis-aligned trying to put it back together one piece at a time & the result is something gets broken or you get a ‘no spark’ problem.
Regarding the "6v or 12v coil" question, lets start by killing a myth. There is no such thing as a 12 volt coil. The only difference between a "6v" coil & a "12v" coil is the internal resistance. But, for the ease of conversation, we all call it a 12v or 6v coil. It used to be before the "Land of Almost Right" started making coils that you could count on a 12v frontmount coil as having 3 ohms of internal resistance & the 6v coils as having 1.5 ohms or less. Thus, thanks to Ohm's Law, you could calculate what additional resistance you needed in the circuit to limit coil current to 3.5 amps. So, you will need to measure the internal resistance of your coil & see what it is. A digital multi-meter has two probes & a switch. Set the switch on resistance. Put one probe on the top of the coil & the other on the pigtail at the bottom. It will give you a reading in ohms. Lets just say it reads 3.0 ohms. Your OEM ballast resistor (which you must use) is about 1 ohm hot. A coil a 3.0 ohms, plus the ballast resistor at 1 ohm (hot) gives you 4.0 ohms resistance in the circuit. Your 12 volt alternator puts out 14.5 volts. You need to determine current (amps). 14.5 v divided by 4.0 ohms gets you 3.6 amps; that's just fine. But, and this is the problem......what if the coil is only 2 ohms? Do the math. 14.5 volts divided by 3.0 ohms gets you 4.8 amps! Not good! And, if the coil is less than 2 ohms (and some are) it will fry quickly. So, to get it to 3.5 amps, you need another resistor in the circuit. Either that, or keep spare $30 coil around. I'd use a "6v" coil & add the additional resistor in order to keep the heat out of the coil. Post back w/ results & any other questions.
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