2004 225 Optimax no power

[toledobasser]

SN#OT874757
2004 Mercury Optimax 225

Unfortunately, I haven't gotten to use my boat in a while. I finally was able to pull it out of the carport and replaced all my batteries. I hooked it to a water hose to make sure it would run before taking it to the lake. It started on the second turn of the key. I let it run for a couple of minutes and turned the key off. When I turned the key back on, there was no beep and the engine did nothing when I turned the key to start. I have no power at all. Even the tilt buttons on the throttle and the engine do not work. I checked the 4 fuses on the engine and none of them are blown. My local shop is unable to even look at it for at least a week, so I was hoping to get some advice from those smarter and more experienced on here. What can I try or what can I check to try to get power back? Oh, also, a couple of days later I was cleaning the boat, since I couldn't take it fishing, and happened to hit the trim button on the engine. It worked. I did not try the ignition because I did not have the key handy. The next time I tried the trim, it did not work. It seems like it has to be something simple but it's beyond me.

[JOE54]

sounds like loose connection , do you have a battery switch in bilge compartment , verify 12v at solenoid and batt grnd connections under cowling , do all pumps /lights switches work on boat, main power relay comes to mind also

[EuropeanAM]

Start at the source- the battery and it's cables/connections.

Keyswitch harness (cannon-plug) may need to be cleaned, male pins spread SLIGHTLY with an exacto knife, then reinstall into it's retainer.

Also make sure lanyard is in the ON position.

[toledobasser]

sounds like loose connection , do you have a battery switch in bilge compartment , verify 12v at solenoid and batt grnd connections under cowling , do all pumps /lights switches work on boat, main power relay comes to mind also

I do not have a battery switch in the bilge compartment. I have one to add once I get this issue fixed. I just installed new batteries and all the connections are clean and snug. I do have power to all the switches/lights/pumps when I turn on the main power switch under the throttle control.

[toledobasser]

Start at the source- the battery and it's cables/connections.

Keyswitch harness (cannon-plug) may need to be cleaned, male pins spread SLIGHTLY with an exacto knife, then reinstall into it's retainer.

Also make sure lanyard is in the ON position.

I replaced the batteries the day before I started the engine and then had this issue. All connections were clean and snug and have been removed and replaced and tightened well. Forgive my inexperience but are you talking about the keyswitch harness at the dash or at the engine? I did remove and replace the kill switch multiple times to be sure that was not part of the issue but that should not have made the trim not work.

[JOE54]

engine connection under cowl from key switch , also wiggle every wire and connection under there on stbd side including main power relay plug

[toledobasser]

engine connection under cowl from key switch , also wiggle every wire and connection under there on stbd side including main power relay plug

Thanks for the suggestion. I am away from my boat working for the weekend. I will take another look when I get home tomorrow.

[smoken86]

Since it seems to have started when you put new batteries in I would get a meter start checking the basics. Power at the engine from the battery and the cable itself. Don't forget to check the grounds as well.

[FeFanatic]

If it was fine before you replaced the battery then go back over your work. The motor trim/start, and charging system comes from the positive cable from the motor. It would not affect any of your lights, horn, gauges, or anything else that is part of the boat itself. Make sure that positive and negative cables are installed properly and tight.

[toledobasser]

If it was fine before you replaced the battery then go back over your work. The motor trim/start, and charging system comes from the positive cable from the motor. It would not affect any of your lights, horn, gauges, or anything else that is part of the boat itself. Make sure that positive and negative cables are installed properly and tight.

I started it and ran it on a hose after I replaced the battery. I ran it a couple of minutes, turned it off and went to start it again and had no power at all to the engine. Power to the lights, pumps and all works fine.

[Savage]

Test the Main Power Relay

[EuropeanAM]

And disconnect/check those battery connections. Always start at the source....

[toledobasser]

Just an update for all that were willing to give advice. I have taken it to my local shop. They can’t figure out what is going on. They put a remote starter on it and it didn’t work. One of the guys looked into the female side of the key switch harness and said one of the holes is completely burned out. No metal sleeve at all. None of the make pins look burned but I don’t know what it should look like. Anyway, they say that is definitely an issue but they said the trim should not be affected by that. They put a new trim relay in and it didn’t work either. He said when he pushes the trim button he can hear the relay pop and then nothing works. Leave it alone for 30 seconds or so and it resets or cools off or whatever and the same thing happens. He hooked a small battery directly to the trim module and the trim worked, so he said the trim module is ok but doesn’t understand why it’s not working. So they are sending me to another shop where the guy has more equipment and a wiring schematic and said he would have to go all through the starboard side of the engine checking things until he figures it out. I’m at a loss and that’s why I have it at a shop but I appreciate the willingness to give advice from everybody on here. I’ll update when it gets figured out.

[toledobasser]

I used to know how to post pics but I can’t now

[smoken86]

Sounds to me it shouldn't have been at that shop originally. Sound to me to be a bad ground or power cable or something not hooked up correctly. Need to isolate the engine from everything else and hook up things one at a time. From just reading the posts it seems something is tripping the main relay.

[EuropeanAM]

Battery or Battery cable connection problem... or grounds for the electrical plate are poor. Start with the battery and battery cables.... then move to the engine end of those cables, and if still not corrected, check electrical plate grounds (bolts to block with three (3) screws).