Help troubleshooting dead 3.0 Merc

[ttugrad]

2007 Merc 3.0 TKS with Alpha 1 outdrive in a Larson SEI 180

All prelaunch spring maintainace done, boat ran great with muffs and for the first 40 min after launch. Ran it through its paces from idle to WOT after warmup, no problems. Took it to my favorite fishing spot slowed down, put it in neutral then reverse to position myself and engine dies. On attempt to restart, I have no gauges, no buzzer and motor dosen't even attempt to start. Ended up using my trolling motor to get the 5 miles back to the ramp.

What I tried:
Checked all fuses, popped and reset 50A fuse on the engine. Checked all connections to the from the fusebox, all connections from the battery. Switched the battery with one of my trolling bats, nada. Last thing I did was bridge the connection after the 50A fuse on the engine to check for power..nothing. I also toggled the kill switch back and forth several times.

This has to be electrical, right? There was no burning smell or obvious short anywhere and I am a little puzzled. Could the ignition tumbler be bad, neutral switch like on cars or perhaps bad kill switch? I need help!

 

[tractoman]

Re: Help troubleshooting dead 3.0 Merc

You'd get gauges with the kill switch active. Have you looked at the wiring on the ignition switch? It sure seems electrical from the description. I would make sure tha battery cable connections are bright and tight. Also, see if you can jump the ignition switch. Sounds like a wire came loose to me. Post what you find.

 

[ttugrad]

Re: Help troubleshooting dead 3.0 Merc

you sure about the gauges with the kill switch? Problem is I have no idea how to dissasemble the dash to get to the ignition.

 

[tractoman]

Re: Help troubleshooting dead 3.0 Merc

Your boat gauges will work, and the engine will turn over when the kill switch is in the kill position. It won't start or run though. This is true on my boat anyway. Can you lay under the helm and see the back of the ignition switch?

 

[ttugrad]

Re: Help troubleshooting dead 3.0 Merc

nope, it is buried near the guages. I would have to take the dash apart

 

[ttugrad]

Re: Help troubleshooting dead 3.0 Merc

One more interesting thing..I never lost my trim, that and the trolling motor are the only things that work.

 

[achris]

Re: Help troubleshooting dead 3.0 Merc

Trim pump runs through different wiring. Only thing in comon is the battery.

You need to break out the multimeter and do some troubleshooting. Start by checking the voltage on the main wire on the starter motor. Remember to check both the lug on the end of the cable and the termainl post itself. That will help confirm a good connection at that point. Next move to the lugs on the back of the 50A breaker on the engine. Check for power on both terminals. Don't foget to check the negative cable connection on the engine block.

If all things are good to this point you are going to have to check the fuse in the harness for the key switch. There is a 20A fuse in the red wire. If that pops then the gauges will not light up when the key is turned. If you find a popped fuse, you'll need to find out why it popped. I've also had a friends boat with a bad connection (slight corrosin on the end of the fuse) in that particular fuse holder....

Good luck,

Chris......

 

[Don S]

Re: Help troubleshooting dead 3.0 Merc

Checked all fuses, popped and reset 50A fuse on the engine. Checked all connections to the from the fusebox, all connections from the battery.

Did you check the above with a meter, or just look at it? You need to verify you have power to and from all those items in order to track down where the power stopped.
With a DVM, set on DC Volts, put the black lead on a good clean ground and check for voltage first at the 50A fuse. BOTH terminals should show battery voltage.

 

[ttugrad]

Re: Help troubleshooting dead 3.0 Merc

time to invest in a multimeter..will do so, check it all out and report back with my results.

 

[ttugrad]

Re: Help troubleshooting dead 3.0 Merc

Ok..have multimeter and found blown 15A fuse on the rear of the engine. I am so new to this that I didn't know that there were any fuses located the wiring harness. Replaced fuse, attempted to start and fuse blew again. Going to check and see where it is comming from.

Thanks for the help

 

[ENSIGN]

Re: Help troubleshooting dead 3.0 Merc

check the 90A fuse on the starter soliniod,when it blows it kills everything