2003 60hp 4 Stroke EFI Relays

film495

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I was messing with my Mom's boat. Well, getting it going for the first time in 3 years. Seemed pretty good, and then ran into an issue. Cut out once, just stopped and could not restart for a minute, then it got going. It was electrical, just cut out, and then no start. Waited about 30 seconds contemplating and then it started and ran fine.

Couple days later, boat in water on a dock, several heavy rainstorms over a few days. Went to try it and it would not start. Definitely electrical, the gauges were all over the place, and messing with it, noticed the trim did not work either. I researched this, and I guess the trim relays can cause that.

OK, point being, I think I solved it, but as with one question, answer it and get more. I took the relays off and cleaned the connections and put them back. Boat seems to run and work fine. There are three relays in a vertical row on the back of the motor. If two are trim, what is the third one for, and they appear to all be the same part number 882751. What is the third relay for?
 

dingbat

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Nov 20, 2001
Messages
16,066
I was messing with my Mom's boat. Well, getting it going for the first time in 3 years. Seemed pretty good, and then ran into an issue. Cut out once, just stopped and could not restart for a minute, then it got going. It was electrical, just cut out, and then no start. Waited about 30 seconds contemplating and then it started and ran fine.

Couple days later, boat in water on a dock, several heavy rainstorms over a few days. Went to try it and it would not start. Definitely electrical, the gauges were all over the place, and messing with it, noticed the trim did not work either. I researched this, and I guess the trim relays can cause that.

OK, point being, I think I solved it, but as with one question, answer it and get more. I took the relays off and cleaned the connections and put them back. Boat seems to run and work fine. There are three relays in a vertical row on the back of the motor. If two are trim, what is the third one for, and they appear to all be the same part number 882751. What is the third relay for?
Guessing, but my money is on the fuel pump relay
 

dingbat

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Nov 20, 2001
Messages
16,066
I guess the same. Makes sense, what else could it be?
Turn the key….if it clicks, you’ve figured it out
Should be a timer involved (turn fuel pump off) as well if no fuel demand
 

film495

Petty Officer 1st Class
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Apr 8, 2009
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285
Turn the key….if it clicks, you’ve figured it out
Should be a timer involved (turn fuel pump off) as well if no fuel demand
oh, you can audibly hear the relays click? do they fail open or closed? I would have thought it would just fail open, and the trim would just not activate up or down, but it seemed to fail closed, and the ignition did not work, and the guages were all over the place, so - anyway, that seems like hokey engineering to me, cause if the boat runs, but the trim doesn't work, you can still just adjust the trim manually as needed. I guess I don't know enough about how relays work.

My concern is that cleaning the contacts did nothing, and whichever one was sticking closed, is still going to do that again, and whatever I did was just concicental. I don't see why a maybe lightly oxidized or tarnished contact would make it fail closed. So, if I had to guess - it is whatever mechancial happens inside he relay is failing intermittently and it will do the same thing again. I should probably just replace them.
 

dingbat

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oh, you can audibly hear the relays click? do they fail open or closed?
Unless you have a schematic, you’re have no idea how the relays are used or if they are NO or NC in the logic (circuit).

Most EFI control the HP fuel pump through a series of interlocks. If any of the interlocks fail, ECU will shut down the pump and disable the ignition as a fail safe.

You really need a schematic, our a good understanding of the control circuit, to effectively troubleshoot this problem.
 

film495

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Apr 8, 2009
Messages
285
as an aside, same boat and motor, not to start another thread. this is a 60hp four stroke mercury on a 16 foot Lund. It will plane, but it has always been a bear. My brother put a prop on it, but honestly, it is worse than before. With just me, will get on plane, 2 people, barely, 2 people and a dog, not gonna ever get there. How does prop pitch affect out of the hole. Once it is on plane, it will go way faster than I'm willing to go - it just won't get there and squats in the water. Am I looking for a lower pitch prop than the stock size, or I could get a few different ones to try I guess. Never switched props before so, need some learning.
 
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