15 amp ignition fuse blows

I

iceman

New Member
Apr 16, 2009
20
FWB, FL
Boat Info
185 Sport
Engines
4.3 Mercruiser
My 2008 185 Sport keeps blowing the 15 amp ignition fuse (under the dash). After out on the water for 30 minutes it just died. Replacing the fuse, the fuse still blows when I turn the ignition to the right ...I hear the warning beep and then it stops, indicating that the fuse is blown (turning the switch to the left powers the radio only and it works).
This has now happened a few times in the past 6 months. I have pulled it out of the water (it was in a lift).
Is there a possible problem with a short in one of the instrument panel gauges or is it an ignition switch problem??
Is there any way to trouble shoot this??
Thanks,
dave
 
Basrd on your description the problem is on the ignitions side. All you can do is trace the wires from the switch in both directions to seehere the short is. n Sorry there is no easy solution
 
Mr Salt said:
Basrd on your description the problem is on the ignitions side. All you can do is trace the wires from the switch in both directions to seehere the short is. n Sorry there is no easy solution
Click to expand...

There's always the Magic Eight Ball.
 
:smt038GOT IT FIXED!!!

I got lucky and found an independent shop to take a quick look at it (Marine Max said 2- weeks just to take a look).
Turns out the exciter wire (purple) running from the alternator had a nick from rubbing on the engine block. It was resting against the block creating the short. He found it in about 5 minutes of just basic looking around the boat, first under the dash and then the engine compartment. ( i had tried to look around that area for loose connections and wires, but this wire was hiding between altenator and engine block.)
Had the boat back in the water in no time :grin:
 
Similar situation happend July 4th... Bought the boat 2 wks ago, 180 hours on it. 15 amp ignition fuse blew on my 2008 185 sport 4.3 TKS. Before the fuse blew the motor suddenly began skipping at 4400 RPMs (almost WOT) then bounced around between 1000 and 3000 rpm, then fuse blew. Found a 10amp fuse in ignition
 
Found a 20 amp fuse in the ignition slot, should have been 15, replaced with a spare 20 amp fuse that was available because I was dead in the water. Once I made it to safety, engine cooled off for an hour, and I tested the motor without engaging the prop while the boat was still in the water. Eased up to 3000 RPMs and motor bounced between 1000 and 2000 RPMs on its own.
Next morning I used proper 15 amp fuse and when I turned the key it burned out.
Going to track down the purple wire discussed in the previous posts of this thread and will provide updates. I have a video of the tachometer showing the RPMs bouncing around but it was denied attachment to this post because it was too big.
 
Found the same scenario on my boat. Purple wire coming off alternator was pinned against the manifold. Pulled it away from the manifold and examined to find the wire had a bare spot that was melted from the heat of the manifold. Picture attached shows the damaged purple wire. Now I need to figure out the best way to repair the wire and secure it away from the manifold. Clearly this is and engineering oversight as these wires are prone to being damaged with their placement so close to the freaking manifold.
20190708_105928.jpg
 
Mike, glad you could fix it and welcome to CSR! You revived a thread 10 years old...I think that may be some kind of record! You could always cut out the bad section and splice in a new one with proper heat shrink crimps etc. Maybe some wire loom to get it away from the manifold or zip tie it better. Mike
 
Used common electrical tape (temp fix to test) and moved wires outside of contact with the manifold. It worked, yipee! Quick video-link attached to see view successful ignition and then see the wires from a top-down look at the running motor - for the next victim. Next will seal permanently and prolly also encapsulate Purple and Red wires using Black Split Loom Tubing. So glad to have found the old thread and thanks for passing on the knowledge!
https://1drv.ms/v/s!Avv6JdvXzWIgiLYKBBCTWj1nV8N34w
 
Last edited:
Here is to old threads! I have a 2005 185 Sport that was having the exact same problem this spring. Thanks to the tips and suggestions I was able to locate the purple wire coming off the back of the alternator that was rubbed bare from pressing against the manifold. Problem solved! I appreciate the photos and trouble shooting.
 
spikedaddy99 said:
Mike, glad you could fix it and welcome to CSR! You revived a thread 10 years old...I think that may be some kind of record! You could always cut out the bad section and splice in a new one with proper heat shrink crimps etc. Maybe some wire loom to get it away from the manifold or zip tie it better. Mike
Click to expand...
Thanks for your assistance. Same issue yesterday here in Queenstown, New Zealand. Tracked the purple wire down and yep had the smallest of nicks out of it and up against manifold. Taped up and changed fuse and humming again. Thanks for the advice. Hopefully corrected now for the long term. Saved on getting boat mechanic in to sort.
 
You must log in or register to reply here.

Forum statistics

Threads
113,229
Messages
1,428,972
Members
61,117
Latest member
jingenio
Back
Top