Where to start? Ignition issue

[mdolesh]

Is the click you're hearing from the starter solenoid or somewhere else? A lot of times a starter can have a dead spot and you'll only get the solenoid click. If you whack the starter with a hammer you can get it going usually, but sometimes it takes a good whack. If that's the case, I'd probably replace the starter. Another way to check that is to put a voltage meter on your starter and see if you're getting power when you turn the key. You'll need a second person ideally for that. Another option is get a remote start switch. It bypasses any solenoid or switches and puts power directly to the starter when you hit the switch. It's mainly used for working on engines. It'll narrow things down for you.

Thanks! When I hold the crossover down everything sequences like normal...beep, I hear the fuel pump get ready (i think thats what it is) and then when I press the port ignition there is a click. I dont know if its from the starter or solenoid...need to check. What is very strange to me is that when the emergency crossover is not pressed the entire port side everything is dead to the world. No gauges, lights, etc. If it was the starter (or a breaker) wouldn't the gauges still activate?

 

[hughespat57]

One of the key things is the gauges are out also, it doesn't take much to power the gauges, so 0 volts.
now when he uses the jumper button the gauges come up (but no crank).

so far we know:
1. all the batteries checked good
2. port battery powered the blowers and pumps ok when tested, so switch should be good
3. the port engine still has no power, no gauges, no crank
4. the jumper circuit is working, port gauges come up (but still no crank)

Could be loose/burnt positive cable at starter.
Could be a starter issue
but that would mean two problems occurred at the same time. Loss of power and lost starter;
now long cranking, solenoid problem or some related issue could have blown the 90A fuse.

We'll have to see if that's the first problem, and if it just blows again, then bigger problems.

As previous the next easiest test "is there 12volt at the back of the 50A breaker?"
Because if not then the problem is before that, which eliminates a lot of engine harness, helm wiring and other problems.

(And I always recommend check the easy things first, don't jump off the cliff at the get go. Diagnostics is about proving or disproving something specific. Each test should narrow the systems or components involved. Either by proving what works or identify what still does not. Eventually this leads to the failed component.)

 

[hughespat57]

Next steps
So as I said easy first, check 50A for voltage.

If no voltage:
Not so easy, stand on head with voltmeter and get to that battery cable at the starter and check for voltage.
Check the output cable on the 90A fuse for voltage.

 

[HawkX66]

Thanks! When I hold the crossover down everything sequences like normal...beep, I hear the fuel pump get ready (i think thats what it is) and then when I press the port ignition there is a click. I dont know if its from the starter or solenoid...need to check. What is very strange to me is that when the emergency crossover is not pressed the entire port side everything is dead to the world. No gauges, lights, etc. If it was the starter (or a breaker) wouldn't the gauges still activate?

With everything going dead, I'd lean towards a bad battery connection somewhere. I remember cars "back in the day" that I had would do the exact same thing sometimes. I'd twist the battery cable and everything would be back to normal.

 

[CaptRonn]

Thanks! When I hold the crossover down everything sequences like normal...beep, I hear the fuel pump get ready (i think thats what it is) and then when I press the port ignition there is a click. I dont know if its from the starter or solenoid...need to check. What is very strange to me is that when the emergency crossover is not pressed the entire port side everything is dead to the world. No gauges, lights, etc. If it was the starter (or a breaker) wouldn't the gauges still activate?

You are having the exact same problem I had last year. My boat has 8.1's.

Started with a dead battery when trying to start starboard. Replaced battery, still no start, no gauges, nothing. Found the 90 amp fuse blown. Replaced, still no start, and no gauges. Reset 50 amp breaker and it started.

Took boat out, anchored. On restart, starboard dead again. Held emergency start and system energized, started engine but when emergency switch released everything died.

I have replaced the ignition switch, the ignition CB, the 90 amp fuse over the past year. Cleaned all grounds, checked all wires and all cables. The last two items I just did a couple of weeks ago were the MPR and the 50 amp CB after the starboard engine did it again.

The note on mine was this would happen while out on the water, but never happen in the slip. And after failing on the water and coming back, a couple of hours later it would work normal.

After research I found the 50amp CB is the typical culprit as these are not well made. Just as a precaution I went ahead and also changed the MPR as well.

We'll see next time out. As a side note, Mercruiser is no help when requesting technical assistance. They will insist you contact a service center. Also, mercruiser knows there is a problem with the 50 amp CB's, but won't address it.

Good luck, intermittent electrical sucks in no matter what it is in.

 

[mdolesh]

You are having the exact same problem I had last year. My boat has 8.1's.

Started with a dead battery when trying to start starboard. Replaced battery, still no start, no gauges, nothing. Found the 90 amp fuse blown. Replaced, still no start, and no gauges. Reset 50 amp breaker and it started.

Took boat out, anchored. On restart, starboard dead again. Held emergency start and system energized, started engine but when emergency switch released everything died.

I have replaced the ignition switch, the ignition CB, the 90 amp fuse over the past year. Cleaned all grounds, checked all wires and all cables. The last two items I just did a couple of weeks ago were the MPR and the 50 amp CB after the starboard engine did it again.

The note on mine was this would happen while out on the water, but never happen in the slip. And after failing on the water and coming back, a couple of hours later it would work normal.

After research I found the 50amp CB is the typical culprit as these are not well made. Just as a precaution I went ahead and also changed the MPR as well.

We'll see next time out. As a side note, Mercruiser is no help when requesting technical assistance. They will insist you contact a service center. Also, mercruiser knows there is a problem with the 50 amp CB's, but won't address it.

Good luck, intermittent electrical sucks in no matter what it is in.

Thanks! What is a MPR?

 

[mdolesh]

I really appreciate all the input guys! Step one tonight is to check the 50amp breaker for power. I also got the service manual for the engine and I see the power trail a little clearer now. Finally, I found some pictures and videos of the 90amp fuse (definitely NOT what I was looking for last night). It appears that these just melt if there is an issue..? And I should be able to feel or see if its bad.

 

[CaptRonn]

I really appreciate all the input guys! Step one tonight is to check the 50amp breaker for power. I also got the service manual for the engine and I see the power trail a little clearer now. Finally, I found some pictures and videos of the 90amp fuse (definitely NOT what I was looking for last night). It appears that these just melt if there is an issue..? And I should be able to feel or see if its bad.

Check it with a multi meter, you won't be able to see it failed by looking at it.

An MPR (main power relay) is one of several relays on the engine. BTW, my experience is with 8.1's, so I'm not sure how your engine is configured. These relays are easy to swap out, and run about $20.

 

[mdolesh]

Back on the boat...no power at the 50amp breaker. I could get a circuit tester on the hot main cable going to the starter. Full power getting there but not at the starter or the 90amp fuse. (I also noticed the port starter has been replaced at some point). To double check what I was doing I repeated the same on the starboard and got readings at all points. So now, is it safe to assume it's the 90amp fuse? If so, how in the holy hell does one replace that? I could barely find it and let alone get a meter on it. Thanks again for all the advice!

 

[hughespat57]

Be sure battery switch is off!!
because there is no way you won’t be getting wrench or socket on that and not hit the engine too

see picture
The eye is on the starter terminal
The fuse slips over a stud and the wire will be under the nut
Remove nut, wire, fuse
New fuse, wire, nut
tighten firmly but dont crush it

 

[mdolesh]

One thing I didnt mention...is that both motors were pulled this winter and transom assemblies replaced. Any chance this is related? This was the 4th time using the boat since the repair. Just curious how I should approach the shop that did the work. Could this have been from something they did or didnt do? Thanks!

 

[scoflaw]

I wouldn't blame anyone for a blown fuse, no joke getting at that on the port engine. That's the reason I relocated mine.

 

[mdolesh]

I wouldn't blame anyone for a blown fuse, no joke getting at that on the port engine. That's the reason I relocated mine.

I agree...and it was several uses later. Just wanted some feedback. Where did you relocate it to?

 

[hughespat57]

One thing I didnt mention...is that both motors were pulled this winter and transom assemblies replaced. Any chance this is related? This was the 4th time using the boat since the repair. Just curious how I should approach the shop that did the work. Could this have been from something they did or didnt do? Thanks!

Not at this point,
Check over the alternator feed wire and the wire from the 50A down to the fuse at the starter.
Look for any chaffed points or pinched points that may have caused a short and blew the fuse.
Could be normal age or maybe they forgot to secure the wires or pinched one.

Buy about four fuses, this could be a repetitive process. (I know that sucks)
Once you eyeball everything turn the battery back on and cross your fingers.

If it blows immediately, then you need to replace it again
and start disconnecting things like the alternator and the 50A leads,
if it blows again something would have to be chaffed or shorted on the block

If not then it's likely a shorted alternator diode bridge, or downstream from the 50A circuit breaker.

remember diagnostics:
isolate systems, test, eliminate systems, repeat...

 

[hughespat57]

I agree...and it was several uses later. Just wanted some feedback. Where did you relocate it to?

Please don't; At least understand the risks
I'm not trying to disparage @scoflaw, he is an experienced operator, he and I have had this discussion before.

It was added by Mercriuser because there was no protection against shorts for the section of wiring from the starter to the alternator and the 50A main breaker. Those wires are significantly smaller then the battery cable to the starter. They can over heat and cause a fire long before the battery cable would get warm.
Circuit protection needs to be at the power source where wire changes to smaller size (branches)
FYI - ALL modern automobiles now have a similar fuse for the alternator due to fires.

 

[mdolesh]

I cant imagine changing that fuse once...let alone several times. How?? I can barely even see it and get a meter on it. I won't move it. I'm not that handy.. Lol.

 

[scoflaw]

I agree...and it was several uses later. Just wanted some feedback. Where did you relocate it to?

At the alternator, the rest of the system is protected by the 50 amp breaker . Wire chafe through is highly unlikely protected by a loom.

 

[hughespat57]

This is the third thread recently about this fuse. There is one possible, practical safe way to change this PITA.
Consider this, the first is the current Mercruiser wire routing. The second is a safe alternative. It would require a good length of heavy gauge wire and some proper routing and securing. At 90A circuit would need #4 AWG cable at 15 feet #3 AWG at 20 feet..

 

[scoflaw]

Usually that 90 can last quite a while on the starter. Corrosion seems to be the killer. So be mindful of that, give it a squirt of something every now and then

 

[89P270]

After reading, my two cents, based on the clicking, is the switches and fuses are fine as the gauges have power and the starter solenoid clicks. It would seem the starter solenoid or voltage regulator (seen in the diagram at the top right?) is bad. Or, as another suggested, corroded battery cables not allowing full load through them to starter. As Hawk suggested, whack the starter to see if that will turn over the motor. Please let us know when you figure it out.