I have an older Tecumseh 7hp, H70, with no spark. The coil tested bad so I replaced the coil with a new coil. The points were pitted a bit so I replaced those also and put on a new condenser. The engine still did not have spark. I removed the coil ground wire which did not help.
I checked everything out a few times and no spark. I tested the coil and it tested ok. I had some other stock so replace the coil, points and condenser with new parts again and no spark. I checked everything a few times, took everything off and on a few times checking for mistakes but no spark. The flywheel magnets seem to have good strength.
I was frustrated so removed the condenser and points and installed a Megafire module. I wired it up and still no spark. I’m checking spark with two different spark testers which I checked on another engine and they work fine.
The Megafire is attached to the block and tested for being grounded with a multimeter. The short wire on the coil goes to ground. The coil long wire runs to the Megafire plus. It was spliced to run to the shut off switch but not attached. It is not touching anything. The Megafire minus terminal wire runs to ground. The wiring has been checked several times. No spark.
At first when I replaced the points assembled everything and pulled the cord to get spark. That was a lot of work so for testing I’m turning the flywheel by hand past the coil. I have the flywheel magnet position marked on the outside to insure I’m causing the magnets to quickly
pass by the coil. I had a coil tester setup I made with an old engine and moving the flywheel quickly by the coil was enough to get a spark so I think doing that now is enough to cause a spark.
Given the failure to get spark I checked the flywheel magnets. There are two magnets. I have installed Megafires in the past with two magnets and it worked so think that part is ok.
One of the magnets is north and one south. I checked online and Ed Stoller page about this stuff. He shows and old Tecumseh H70 flywheel with the magnet polarity as follows. Looking from the center of the flywheel to the magnets on the inside the left magnets is south and the right north. Mine are reversed. The one of the left is north and the right south. I don’t that that would make a difference for the points system but may for the Megafire. I’m not sure.
There is some glue residue around the magnets. I don’t know if that was from the factory install or someone later put the magnets on. ? The flywheel is a 13-0-44 which is for an H70 so should be ok.
Given that installing points is a fairly simple thing and so is installing a Megafire I’m lost.
I checked for voltage at the coil sparkplug. I moved the flywheel by hand quickly over the coil and only get a few volts out on the AC and DC scales. The voltage may be low or it may be too fast to get recorded by the mulitmeter. Since there are not points to open maybe the field is not collapsing quickly enough to induce a large voltage.
I’ve installed points a number of times and a few Megafires and all went well but not this time. Any input would be appreciated.
I checked everything out a few times and no spark. I tested the coil and it tested ok. I had some other stock so replace the coil, points and condenser with new parts again and no spark. I checked everything a few times, took everything off and on a few times checking for mistakes but no spark. The flywheel magnets seem to have good strength.
I was frustrated so removed the condenser and points and installed a Megafire module. I wired it up and still no spark. I’m checking spark with two different spark testers which I checked on another engine and they work fine.
The Megafire is attached to the block and tested for being grounded with a multimeter. The short wire on the coil goes to ground. The coil long wire runs to the Megafire plus. It was spliced to run to the shut off switch but not attached. It is not touching anything. The Megafire minus terminal wire runs to ground. The wiring has been checked several times. No spark.
At first when I replaced the points assembled everything and pulled the cord to get spark. That was a lot of work so for testing I’m turning the flywheel by hand past the coil. I have the flywheel magnet position marked on the outside to insure I’m causing the magnets to quickly
pass by the coil. I had a coil tester setup I made with an old engine and moving the flywheel quickly by the coil was enough to get a spark so I think doing that now is enough to cause a spark.
Given the failure to get spark I checked the flywheel magnets. There are two magnets. I have installed Megafires in the past with two magnets and it worked so think that part is ok.
One of the magnets is north and one south. I checked online and Ed Stoller page about this stuff. He shows and old Tecumseh H70 flywheel with the magnet polarity as follows. Looking from the center of the flywheel to the magnets on the inside the left magnets is south and the right north. Mine are reversed. The one of the left is north and the right south. I don’t that that would make a difference for the points system but may for the Megafire. I’m not sure.
There is some glue residue around the magnets. I don’t know if that was from the factory install or someone later put the magnets on. ? The flywheel is a 13-0-44 which is for an H70 so should be ok.
Given that installing points is a fairly simple thing and so is installing a Megafire I’m lost.
I checked for voltage at the coil sparkplug. I moved the flywheel by hand quickly over the coil and only get a few volts out on the AC and DC scales. The voltage may be low or it may be too fast to get recorded by the mulitmeter. Since there are not points to open maybe the field is not collapsing quickly enough to induce a large voltage.
I’ve installed points a number of times and a few Megafires and all went well but not this time. Any input would be appreciated.