Photo of the main breaker ontop of the motor?

J3ff

Hey all - does anyone have a photo of a working main breaker on the top of a Mercruiser 5.7?

Have been overhauling the engine on the 270 all summer long, new risers, hoses, etc etc.. today was supposed to be the day and guess what.. nothing, zero crank.  Fuel pump kicks on no problem. Couple of beeps, but other than that the motor doesn't even attempt to start.. yes the safety switch is in the correct position and when you turn it off and on you get a nice loud beep as usual. 

I'm looking to find a photo of that main breaker on a working motor. Everything I google is just the switch itself and I can't tell what it looks like when it's tripped vs working. 

Right now I cannot push the red button back in, even with a huge amount of force.. do these things just perm break??

Formulaben

I could be wrong, but I think that is what they look like un-popped.  

Here is how I would troubleshoot:

1)  Verify battery switch is in correct position and batteries are hooked up appropriately.

2)  Have someone smack the starter solenoid with a hammer with the key on start.

3)  When you say "safety switch" do you mean the lanyard, or neutral safety switch?  The neutral safety switch could have gotten mis-rigged or broken.  Try wiggling/moving the throttle with the neutral button pushed in while starting.

4)  Check/replace the start relay.

5)  Jump the starter directly to verify the starter works.

J3ff

Yeah, the more and more I see it - it doesn't look popped. 

#1 is correct. 

#2 tomorrow

#3 for sure is fine. 

#4 tomorrow

#5 tomorrow.

Thank you!

J3ff

she starts just fine if I jump the solenoid with the key set to run

Willhound

So, bad or stuck solenoid? Maybe from sitting in the salt air?

J3ff

Let the boat run for 10 mins.. turned her off, turned the water off, thought "let me just try the key now.." boom started right up no jumping needed. Hoping this means that solenoid is bad.. does that sound right? 

Formulaben

J3ff said:

she starts just fine if I jump the solenoid with the key set to run

I just want to be clear here, are you talking the SLAVE (start) solenoid near the ECM, or the STARTER solenoid, which is mounted on the starter itself? 

The way I understand it (and that's questionable!), Mercury has a relay they call the "start solenoid" (I call it the start relay, as per #4 above) and it's next to the big red circuit breaker adjacent the ECM.  Mechanics call it a slave solenoid, since it is a solenoid/relay for the "other" big solenoid on the starter.

J3ff

Slave solenoid right next to the ECM.

She started just fine for the rest of the day with the key. Ordered a new SLAVE solenoid.. hopefully that's it.. how annoying after basically changing everything out on the motor that needed it over the summer (hoses, risers, all fluids, spark plugs, wires, etc etc etc..) to have it not turn over yesterday and then today it appears to be fine after one manual start jumping the slave solenoid. 

The only weird thing vs your video is that I didn't hear a click ever. Tried it 10 times with no click. 

Formulaben

J3ff said:

The only weird thing vs your video is that I didn't hear a click ever. Tried it 10 times with no click. 

That makes sense; if it was a bad starter, then you'd hear the click of the starter solenoid, but the bad starter isn't turning.  The fact that you didn't hear the click tells me that you had either a bad/stuck slave solenoid or a bad/stuck starter solenoid.  My only concern is that if you have an intermittently bad starter solenoid, then the replacement slave solenoid isn't solving anything.  Hopefully that's not the case!