Fuse problem on 89 Merc 100hp

[sdpikehntr]

There is an in line fuse that is set beside the starter that continues to blow, It is not directly attached to the starter, but when it is blown the motor has no Elec. power. When I replace the fuse, it will start and run fine, but some time in the motor use the fuse blows again and will not start. The first time this happened it also blew the fuse for the trim/tilt.

I have traced all the wires and have not found any with exposed bare wire, I have checked both on the motor and back to the control/ignition. I am at a stand still and just wondering if there is a relay on the motor or a converter on the motor that may cause it.

[boatfixer]

That fuse protects the wire that runs to the key switch and it also provides the feed for the trim and tilt switch. Since there is no ground for the TnT switch, the first thing I'd look at is the ignition switch. Its possible the switch is shorting to ground internally or the wires on the back of the switch may be shorting to ground. There is also the possibility of one of the solenoids for the TnT is shorting as well as one of the wires shorting to ground at or near the solenoid. If no obvious short is found, check for tight connections and even clean all connections at the solenoids and key switch. Poor, loose, or dirty connections cause resistance and can also blow fuses.

[sdpikehntr]

Ok, Thanks. I will try taking my shift/ignition control apart and look at the connection. Tonight I cleaned and looked at all the wires on the motor and they all appear ok. I also have a trim/tilt switch on the Bow control panel it worked earlier but now it does not, I think this may be part of the problem as well. What do you think?

[marine_man]

It's certainly possible.

Can you remember what you were doing when it blew the fuse the last time?

marine_man

[sdpikehntr]

I Had replaced the fuse on the water, started the motor and headed back to the dock (just start and run). By the time I got back to the dock it was blown and I had to load with out the motor, as it wouldn't start again. I checked all the wires agaon this weekend and all the wires appear tp be just fine. I plan to check the wiring inside the control unit tonight to see if there are some issues in there. What are you thoughts????

[marine_man]

Did it pop when you hit the trim / tilt vs a random time popping? That would help narrow it down.

If you're certain it's not trim / tilt actuated, then you've got a project ahead of you... I'd see if you can find a different key switch / borrow a short keyswitch harness to rule out the entire harness right away (since it's just a matter of plugging a different harness in).

marine_man