mattsmall1972
Petty Officer 1st Class
- Joined
- May 14, 2006
- Messages
- 238
After working on my 1978 Cobia OMC 2.5L Stringer 400, it's finally running. Buddy and I did the first water trial and had some issues. We've worked on the issues somewhat and I'd like your response on these items:
1) Overheating. The boat was running great at WOT until it began to overheat. We kept a close eye on the temp gauge and let it relax a bit before trying to move again. We found out that it cools fine at idle speeds, but overheats at higher RPM. Our initial thought was that the thermostat was likely stuck. We yanked it and found that a large amount of rust pieces was blocking up the port leading from the thermostat housing to the heads. I cleaned out the thermostat housing and tested the thermostat - it appears fine at this point. The thinking is that the large pieces blocking the hole allowed enough water to cool at idle but not enough to provide cooling for higher rpms. This has a brand new impeller, btw.
Since running yesterday, it seems we've run into some electrical issues
2) The motor wouldn't turn over when I turn the igntion key. I finally touched the solenoid to the positive on the battery and the motor turned over. It seems like I have a short in the ignition wires somewhere? What else is interesting is that now it works from the key after doing this.
3) Along with the ignition issue, now the tilt won't work from the switch. It does work from the solenoid, however. I think it goes hand in hand with the starter acting funny. It doesn't even click.
4) The trim went out altogether. It doesn't even work from the solenoids.
Your thoughts, please.
1) Overheating. The boat was running great at WOT until it began to overheat. We kept a close eye on the temp gauge and let it relax a bit before trying to move again. We found out that it cools fine at idle speeds, but overheats at higher RPM. Our initial thought was that the thermostat was likely stuck. We yanked it and found that a large amount of rust pieces was blocking up the port leading from the thermostat housing to the heads. I cleaned out the thermostat housing and tested the thermostat - it appears fine at this point. The thinking is that the large pieces blocking the hole allowed enough water to cool at idle but not enough to provide cooling for higher rpms. This has a brand new impeller, btw.
Since running yesterday, it seems we've run into some electrical issues
2) The motor wouldn't turn over when I turn the igntion key. I finally touched the solenoid to the positive on the battery and the motor turned over. It seems like I have a short in the ignition wires somewhere? What else is interesting is that now it works from the key after doing this.
3) Along with the ignition issue, now the tilt won't work from the switch. It does work from the solenoid, however. I think it goes hand in hand with the starter acting funny. It doesn't even click.
4) The trim went out altogether. It doesn't even work from the solenoids.
Your thoughts, please.
