Re: 1973 Johnson 85HP Cylinder Order
235 vdc gives a p-p avg of 130 v ac,, little low but will still fire the coils give you abour 26.1kvolts out of the coil.
could be connections, and yes it did take some time to discharge the cap at 10meg ohm resistance, can sub a smaller resistance value to decrease discharge time, or short your leads together to discharge the cap before making next measurement.
seems lke you are loosing a litle bit of voltage in the amp section but it is switching.
new coils will definately improve the performance and probaly get you through the season but that amp may need replacing or it may have been a dirty contact.
I believe the coils ohm out at 2k ohm new so you may try removing the coil from the amp, connect a 2k ohm resistor to the terminal on the amp and the other side to ground and try to take a measurement that way or wait till your new coils come in to re check after installing them
***NOTE*** never check the output of your amp with no load on the terminal, sure way to blow the circuit, have to have that 2k ohm load on the output.
it may be your coils are putting more of a load or less of a load on the amp and causing the lower reading on the output. when a coil starts going bad it can and will take out the rest of the components in the ignition eventually.
If after replacing the 4 new coils your readings still stay under 150vac then the amp will need replacing also, keep in mind you HAVE to have 150vac coming in on the brown wires in order to get 150vac out of the amp, so make sure you get 150vac in before throwing any more parts at this ignition system.
a bad rectifier will also take out an ignition system.
troubelshoting matrix says to disconnect the rectifier while performing tests, i did not disconnect mine as i ohmed it to make sure the diodes were good and i got good readings from the system.
I know what you mean not enough hands, i used gator clips jumper wires to do mine, and a remote starter hooked to the solenoid to turn it over.
I will try to snap the pics of the throttle assy tonight after work and get them sent to you for the lync n sync.
235 vdc gives a p-p avg of 130 v ac,, little low but will still fire the coils give you abour 26.1kvolts out of the coil.
could be connections, and yes it did take some time to discharge the cap at 10meg ohm resistance, can sub a smaller resistance value to decrease discharge time, or short your leads together to discharge the cap before making next measurement.
seems lke you are loosing a litle bit of voltage in the amp section but it is switching.
new coils will definately improve the performance and probaly get you through the season but that amp may need replacing or it may have been a dirty contact.
I believe the coils ohm out at 2k ohm new so you may try removing the coil from the amp, connect a 2k ohm resistor to the terminal on the amp and the other side to ground and try to take a measurement that way or wait till your new coils come in to re check after installing them
***NOTE*** never check the output of your amp with no load on the terminal, sure way to blow the circuit, have to have that 2k ohm load on the output.
it may be your coils are putting more of a load or less of a load on the amp and causing the lower reading on the output. when a coil starts going bad it can and will take out the rest of the components in the ignition eventually.
If after replacing the 4 new coils your readings still stay under 150vac then the amp will need replacing also, keep in mind you HAVE to have 150vac coming in on the brown wires in order to get 150vac out of the amp, so make sure you get 150vac in before throwing any more parts at this ignition system.
a bad rectifier will also take out an ignition system.
troubelshoting matrix says to disconnect the rectifier while performing tests, i did not disconnect mine as i ohmed it to make sure the diodes were good and i got good readings from the system.
I know what you mean not enough hands, i used gator clips jumper wires to do mine, and a remote starter hooked to the solenoid to turn it over.
I will try to snap the pics of the throttle assy tonight after work and get them sent to you for the lync n sync.
even with some reading glasses I couldn't see well enough to do a good job soldering. Made a mess of my breadboard but apparently nothing shorted out. Put it all in a little black box to make it pretty. I think I spent about $2.50 for the rectifier (same as a pack of 4 diodes), $2.50 for the cap, and a buck for a pack of resistors. The expensive part was a set of cable leads that were around $7. I remember when Radio Shack actually used to have electronic stuff. Now it is all crammed into a tiny spot in the back of the store. Couldn't even find their tube testing station!!!!!!!