fireman57
Captain
- Joined
- Aug 24, 2004
- Messages
- 3,811
Re: Again with the '78 70hp evi
Looking at the OEM shop manual the thermostat wire hooks to a buzzer and then to one of the M connectors on the ignition switch then there is a black wire that runs from the same M connector to the #1 coil to short it out if there is a problem. The yellow and black connects to the other M terminal in the ignition switch. Evidently there is a safeguard on this engine to knock out #1 coil if there is an overheat problem. I know that it is not overheating as we have moved the telltale to the top cylinder per an OMC bulletin and the heads are just warm. the thermostat itself might not be working because the heads never got too hot to hold your finger on them for at least a long ten count. We had swapped control boxes out so there is no buzzer connected yet. Just guessing that it was wired directly for it to kill the #1 coil. Will rectify that situation now that the problem has been isolated.
As far as pumping the primer bulb to keep it going at one time we were dealing with two problems at once. got fuel fixed then the dropped cylinder came into play.
Looking at the OEM shop manual the thermostat wire hooks to a buzzer and then to one of the M connectors on the ignition switch then there is a black wire that runs from the same M connector to the #1 coil to short it out if there is a problem. The yellow and black connects to the other M terminal in the ignition switch. Evidently there is a safeguard on this engine to knock out #1 coil if there is an overheat problem. I know that it is not overheating as we have moved the telltale to the top cylinder per an OMC bulletin and the heads are just warm. the thermostat itself might not be working because the heads never got too hot to hold your finger on them for at least a long ten count. We had swapped control boxes out so there is no buzzer connected yet. Just guessing that it was wired directly for it to kill the #1 coil. Will rectify that situation now that the problem has been isolated.
As far as pumping the primer bulb to keep it going at one time we were dealing with two problems at once. got fuel fixed then the dropped cylinder came into play.
so sad!