mguidry629
Seaman
- Joined
- Sep 19, 2011
- Messages
- 53
1987 Mercruiser 5.7
I currently have an automotive HEI Distributor (My Delco EST arrives today and will be installed ASAP). It has one red wire (12v) and one gray wire (to Tach). Upon researching some wiring diagrams, I don't think the red wire is factory. It was probably wired up by the PO that installed the HEI Distributor.
Once the motor warms up, it dies sporadically (instantly, like turning off the key). After some testing and troubleshooting on the water I found that I was not getting 12v to the red wire with key on, but it was pulsing with the starter (test light was flashing).
When the engine is cold, that wire is getting 12v with key on (engine runs fine). When the engine warms up, the wire only gets voltage when the starter is engaged (no voltage with key on, engine won't run). So the engine ignites and tries to start until you disengage the starter and.... nothing. I followed the red wire which goes to one of the smaller posts on the starter slave solenoid (2 large posts and 2 small). A wire goes from that same post to the shift cutout switch.
I believe this engine had the Thunderbolt IV ignition and was converted to HEI. But I've had the boat in the water several times and never had any problems like this before. However it's wired it was working fine, now it's not.
Could this be the solenoid itself? Are they suseptable to heat failure? Should the 12v wire going to the distributor (or coil actually) be connected to this solenoid?
I'm going to install the new Delco EST, but I'm afraid I'm going to have the same issues especially if wired from the same 12v source.
Just wanted to add that I recently installed a new thermostat. Old one was non-existent. So motor is running at a warmer temp now.
I currently have an automotive HEI Distributor (My Delco EST arrives today and will be installed ASAP). It has one red wire (12v) and one gray wire (to Tach). Upon researching some wiring diagrams, I don't think the red wire is factory. It was probably wired up by the PO that installed the HEI Distributor.
Once the motor warms up, it dies sporadically (instantly, like turning off the key). After some testing and troubleshooting on the water I found that I was not getting 12v to the red wire with key on, but it was pulsing with the starter (test light was flashing).
When the engine is cold, that wire is getting 12v with key on (engine runs fine). When the engine warms up, the wire only gets voltage when the starter is engaged (no voltage with key on, engine won't run). So the engine ignites and tries to start until you disengage the starter and.... nothing. I followed the red wire which goes to one of the smaller posts on the starter slave solenoid (2 large posts and 2 small). A wire goes from that same post to the shift cutout switch.
I believe this engine had the Thunderbolt IV ignition and was converted to HEI. But I've had the boat in the water several times and never had any problems like this before. However it's wired it was working fine, now it's not.
Could this be the solenoid itself? Are they suseptable to heat failure? Should the 12v wire going to the distributor (or coil actually) be connected to this solenoid?
I'm going to install the new Delco EST, but I'm afraid I'm going to have the same issues especially if wired from the same 12v source.
Just wanted to add that I recently installed a new thermostat. Old one was non-existent. So motor is running at a warmer temp now.
