Sea Ray 2016 270SD: 5 amp fuse on clean power harness blows intermittently

[1896steinway]

Hello, I'm new to the forum and I have a nasty electrical gremlin which the service center cannot re-produce and, therefore, can't fix.


The boat turns off at unexpected times due to the 5 amp fuse blowing on the clean power harness. It is rigged from the battery to the PCM. The boat turns off (fuse blows) while the boat is moving or idle at the dock. I replace the fuse and sometimes it runs for another 45 minutes before dying or it will die multiple times, within 10 minutes, over and over after continuing to replace the fuse. The boat has died under a few conditions: 1) going 30 MPH and I notice the speedometer jump from 30-0 to 30-0, etc. Then when I slow down, it dies 2) boat dies when it is running idle at the slip and 3) boat dies when I leave the slip going 5 mph.

The service center had the boat for 6 weeks and could not re-produce the problem. They ran the boat for a couple hours on the water and idle at the dock and the boat runs fine and will not die. Of course, after they turned it over to me it died after I ran it for a few hours. But still, it can die when I turn on the boat first thing in the morning at the dock. As a Hail Mary, they disconnected the depth sounder (transducer) which, according to the service center, was incorrectly connected to that circuit. So I'll be using the boat as much as I can to see if it will still die with no depth gauge. I understand the only thing that should be connected to the clean power harness is the DTS. I understand it can be a short, water is in the wrong place or a component on that circuit is drawing too much current. They tried to change the key switch to no avail. Another idea is that something could be getting caught/stuck in the transom bilge pump causing a spike in current


Anyone, please help. I have lost almost the entire season.


Thanks in advance.

 

[Seapig]

While I’m not 100% sure, that circuit should go only to the PCM. I’m wondering if there are other circuits tied into it. On my 2012 310, all the “loads” on PCM controlled devices are fused on their power side (relay power).

Id hook up a test light to that circuit downstream of the fuse and then start manipulating harnesses while watching the lamp. If it flickers, dims, or goes out (blown fuse) you’re close to an area where a harness is chaffed to ground.

You could cut the power wire on that clean power harness near the plug near the rear of the engine and power the PCM directly from a battery through a 5A fuse. If something else craps out, you’ll know it’s tied into the clean power circuit.

with automotive stuff we’d splice in lower amp rating fuses into Other circuits that Feed off of the blowing fuse. That way we’d know which “branch” of the circuit is suspect.

 

[1896steinway]

Thanks @Seapig. I’ll pass on your suggestions to the service center. Much appreciated.