I recently bought a 78 402 Mercury boat and it never ran right from the start. I'm completely new to outboards and found through similar forums how to check around these motors. The original problem was an extreme surge I the idle . I cleaned terminals cleaned the carb found bad wirinj on stator so replaced and fiddled with it to no avail. Finally took to a mechanic who found the fuel pump diaphragm ripped ,bad water pump, rebuilt the carb lync and sync and shipped it. It ran good at idle finally but was still really hard to start. Ran it for one day and it died several times but would start again while warmed. Week later ,went to start it cranked and cranked till it finally started and it idled beautifully again. But then it died like I got the kill switch. Wouldn't restart but would try. Checked spark and felt it on my hand but couldn't see it. Looked around and found a Mercury certified tech near me . Told him the scheme and he recommended a dva test of ignition system. He found the stator was putting out almost 500 volts and only 70 were going to the coil and told me to get a switchbox. I replaced the switchbox and nothing, wont start. So I investigated some more. I found 2 volts on the orange kill wire when the ignition is on so I disconnected it and can get it to run but it runs at really high rpms. Bought a dva and measured ohms on trigger stator and coils. The only abnormality is o l on secondary which I put lead from inside where the plug goes to the negative terminal. Both coils are the same. The high rpms made me check tdc and timing was retarded by probably 20 degrees. So I adjusted turnbuckle and made sure throttle plate was closed until it caught up finally. No change at all still high rpms around 1800-2000. Checked voltage with the dva
Blue to ground-250. Red to ground--166. Trigger brown to ground--2.8. Trigger white to ground--2.5. Coil 1 green to ground--194 Coil 2 to ground-- 185. All at 1800 or so rpm. I ordered a trigger and coils but past that I'm afraid I don't know where to go it's driving me mad! Can a rectifier cause this condition? Also I am finding tar like sticky goo all over this motors terminals and trigger. Compression is 150 on both cylinders
Blue to ground-250. Red to ground--166. Trigger brown to ground--2.8. Trigger white to ground--2.5. Coil 1 green to ground--194 Coil 2 to ground-- 185. All at 1800 or so rpm. I ordered a trigger and coils but past that I'm afraid I don't know where to go it's driving me mad! Can a rectifier cause this condition? Also I am finding tar like sticky goo all over this motors terminals and trigger. Compression is 150 on both cylinders
