Join Date: Aug 2006
Location: Arlington, VA
Thanked 11 Times in 9 Posts
Rep Power: 11
As noted above, there are different ways of wiring engines.
Most engines have the starter solenoid wired thru the ignition key, some with a separate starter button.
Most engines have the temp and oil sensors wired thru the ignition key.
Most engines have the guages wired thru the ignition key.
Many engines have the alternator field coil wired thru the ignition key...this provides excitation to the alternator for those which are not self-exciting.
Other accessories may also be wired thru the ignition key on some boats.
With diesels, in general, it is good practice to follow these steps when starting or stopping the engine:
(when starting the engine)
1. Turn on the ignition key
2. Start the engine, either with the ignition key or a separate starter button
3. Check the exhaust to be sure water is coming out
4. Check the oil guage to be sure you have oil pressure
5. Leave the ignition key ON
(when stopping the engine)
6. Press the STOP button or pull the STOP lever
7. When the engine stops, listen for the oil alarm -- it should go off when oil pressure drops -- this tells you that the low oil pressure alarm is working OK
8. Turn off the ignition key
Mark...on most boats, turning off the key with the engine running should not blow the diodes on the alternator; it should merely remove the field current which would stop the alternator output. However, it's still not good practice to turn the key off while the engine is running.
Breaking the connection between the alternator and the batteries, however, will definitely blow the alternator diodes very quickly if the alternator was putting out any appreciable current when the connection was broken. On many boats with the alternator wired thru the battery switch, this is much too easy to do, e.g., by switching the 1-2-Both-Off switch to the OFF position, intentionally or otherwise.
Dockbumdan: you've been a very lucky camper for the past 20 years. Time to mend your evil ways and see if you can do it right for the next 20 :-) And, who knows....if your dockmates on the Sassafras see you doing it right for awhile, they might just invite you along for a sail on their boats!
Last edited by btrayfors; 11-17-2011 at 02:58 PM.