2005 Utopis keeps blowing relays and leaves me stranded

[jlwardn]

A couple years ago I bought a used 2005 Utopia with the Merc Optimax 250. It ran/runs great in the river where I spend most of my time. I took it out on Lake Michigan and at the end of the channel where the boat wakes meet the big lake.....it gets a little choppy. All of a sudden after bouncing around for a few minutes by boat shuts off and won't restart. It just turns over like it is out of gas. After getting towed to a safer spot I start going through the glove box . I find a repair sheet from a marina that replaced a relay after 3 hours of diagnostic for a Stall and no restart issue. I opened the engine and saw a similar relay by itself. It had the same part number so I changed it out. The boat started fine. The relay that I replaced was very hot and one metal lead inside looked a little melted around the plastic. I bought another one just in case.
Ran the boat many many hours( and few weeks)in the river without issue. Once again when I ventured out toward the big lake it happened again. I figured that all the bouncing around was causing the issue since the relay was loose and not tight or bolted to anything. I zip tied it down to eliminate it from moving and bouncing. This season I have only had the boat out a few times on the river. Today it happened again. It seems to happen after the boat has ran for over 30 minutes and once I start going through choppy water. When I replace the relay it is extremely hot and can not be handled with bare hand. I have replaced 4 now. It always happens in the worst spot where I am in the middle of traffic or dangerously close to pier. I can run the boat WOT and run it as hard as I want in the river. It just seems to have issues with waves or wake when the boat has to bounce alot. I can't completely rule out that it still is from the relay boucing around. I zip tied it through the rubber grommet that comes with the new one. The relay is mounted on a wire brace that clips to the rubber grommet. It can be pulled off and that is how I found it when it went bad
At $20 a pop.....I really would like to find the issue. It can't be good that these are getting extremely hot to where it melts a little plastic inside the relay. The number on the relay if for a Mercury Trim(which my boat does not have). It seems to be for a fuel pump or something that would make the boat not start from getting no fuel. When inside the boat the relay is on the left side all by itself.

Anyone have any ideas?

 

[Lumps]

my knee jerk reaction is that you have a short somewhere that makes contact with something it shouldn't when you are bouncing around. this puts more current through the relay then it can handle until it fails. unless there is something wrong with the fuel pump (or what even it is powering) and its that that is drawing too much current.

the only thing I would wonder is why is the relay melting and not the fuse that is protecting the circuit? check the fuse box and see if there are any fuses that are have fuses that are larger amps then the are supposed to be. I bet that the previous owner had a fuse that kept blowing until he put one in that was way too big.

check the fuses. then get the wire numbers / colour of the wires and check the wiring diagram to see what this relay is for. this should start you down the right path to finding the culprit.

 

[AirSniper]

First, I bought a 5 pack "5 Pack OLS 40/30 Amp Waterproof Relay Switch Harness Set - 12V DC 5-Pin SPDT Automotive Relays 12 AWG Hot Wires" for $25 on amazon - get these - they are the relays with harnesses.

second, your harness needs replaced - one of the pins is burned, take a good look at it.

This 5 pack is cheap and will not only fix you, but any merc o/b engine and mercury o/b trim relays.

If, by chance I am wrong on the burnt part (I'm not), know that this is the MPR, "main power relay". It is energized for ~ 3-5 second when the key goes to run (not start). this runs several fuel pumps for a few seconds. When you go to start your engine, turn the key to run & wait for the pumps to stop running before you go to start. That will de-energize your relay with reasonably high amperage going through the contacts...not good for the relay.

you can look at some of my recent posts where i describe similar issues. please update.

 

[jlwardn]

My harness does have one pin that is melted. Thanks for the tip on the replacement. Any ideas what caused this mess in the first place? Something had to short or overheat in order to melt the pin and fry the relay. How long has it been since you replaced the harness? Any further issues? Is the gauge of wire on the new harness the same as factory?
Any additional helps or ideas would be great.

First, I bought a 5 pack "5 Pack OLS 40/30 Amp Waterproof Relay Switch Harness Set - 12V DC 5-Pin SPDT Automotive Relays 12 AWG Hot Wires" for $25 on amazon - get these - they are the relays with harnesses.

second, your harness needs replaced - one of the pins is burned, take a good look at it.

This 5 pack is cheap and will not only fix you, but any merc o/b engine and mercury o/b trim relays.

If, by chance I am wrong on the burnt part (I'm not), know that this is the MPR, "main power relay". It is energized for ~ 3-5 second when the key goes to run (not start). this runs several fuel pumps for a few seconds. When you go to start your engine, turn the key to run & wait for the pumps to stop running before you go to start. That will de-energize your relay with reasonably high amperage going through the contacts...not good for the relay.

you can look at some of my recent posts where i describe similar issues. please update.

 

[AirSniper]

not much info on the subject, but i did find one post somewhere leading me to inspect my harness plug - same as you describe. I'm going on a month or so without issue. The outboard guys seem to find this somewhat common, but they can swap MPR with the trim relays and make it home. I now keep an extra relay in the car & in the boat. I just gave one away to a guy with relay issues on a 72 dodge dart - they are very common.

If i had to guess the root cause, it would be turning the key before the relay cycles off itself. This could internally arc (a cheap) relay - and these are cheap.

The harness seems to be the same or larger wire, no concern since the duty cycle is mild - 5 seconds on...I would recommend using a watertight heat shrink on any splices.

 

[jlwardn]

I bought a harness like you did from Amazon. I received the harness and noticed it was a 5 wire. I only have 4 wires on the one that needs to be replaced. Which harness did you buy? Any further issues?
Thanks for the help

 

[AirSniper]

no further issues, all is good.
I bought the https://www.amazon.com/gp/product/B01MTQNJKM/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
on the page there are diagrams. I believe the center yellow contact is not used - it is normally closed. it should be obvious looking at your setup. I think i recall 2 smaller size wires & two larger sized wires...this should help you figure new connections.
If you need pics, let me know, i should be able to get them easily.

 

[jlwardn]

I bought harness and planned on doing it at the end of the season. Last weekend I was using the boat and after and hour I burned up another relay very close to my house. I put in the new relay that came with the harness. It started the boat and I made it home...just a 2 minute drive at most. This weekend I started the boat and started to drive down the river. Within 3 minutes the boat stalled. Trying to start the boat seemed different.....slower cranking but again acted like I was out of gas or the relay was bad. Not sure what it can be. It is a new relay but not one that says 882751. It is one that you bought from Amazon. Shop can't get me in for a couple of weeks. When I pulled the boat out...I put fuel in to make sure it was not out and gas gauge not working. When I arrived home I tried to get it to run again......no go. I am getting a one loud beep when I try to start and get slower than normal cranking. Battery is fine. Any thoughts or suggestions?

 

[AirSniper]

As i recall, if the relay fails, there is no beep upon turning the key to run. You can test this easily by disconnecting the relay, go to run and see what happens. This can be a good relay indication.