Random no crank on 5.0

[Lancerdad34]

I have been having a random no crank issue when I turn the key to start It is very random when it happens. I carry a jumper wire but so far have not had to jump the selonoid. The way I have got out of it is by moving the batter switch either from all to bat 1 or bat 2. It seems that when I do that the issue goes away. Batteries are both fully charged checked that. Can a selonoid be flakey like that or should I look at the ignition switch?

Thanks for any ideas!
Brian Lake St Clair Mi

 

[alldodge]

Moving the Bat switch should have no effect on starting unless there is a bad connection, but a bad connection normally causes the starter to click or something else.

Might be the key switch, neutral safety switch, slave relay or bad connection between key and starter solenoid

 

[Kola16]

Sounds like your battery switch is bad, but it is easy to test. Does anything else work when you have the battery switch on "all" and your engine won't crank? Do your gauges work? Does your bilge pump work? What voltage are you reading when your switch is on "all" and your engine won't crank?

 

[Bondo]

Ayuh,..... Sounds like corrosion / bad connections,....
Starting at the battery, clean to shiny metal clean, both ends of all the cables, through yer battery switch, to the starter,......

If the problem persists, test the key switch, through the solenoids, with a test light,.....

 

[Lancerdad34]

Sounds like your battery switch is bad, but it is easy to test. Does anything else work when you have the battery switch on "all" and your engine won't crank? Do your gauges work? Does your bilge pump work? What voltage are you reading when your switch is on "all" and your engine won't crank?

Yes everything works fine on all 3 spots on battery switch.

 

[Lancerdad34]

Ayuh,..... Sounds like corrosion / bad connections,....
Starting at the battery, clean to shiny metal clean, both ends of all the cables, through yer battery switch, to the starter,......

If the problem persists, test the key switch, through the solenoids, with a test light,.....

Thanks will take a look Fri!

 

[Kola16]

Yes everything works fine on all 3 spots on battery switch.

Then your battery switch should be good. The next steps would be what Bondo suggested. Clean all battery connections and look for corroded wires.

If that does not do it then put a test light on the signal wire on the starter solenoid like suggested. If it lights up and the engine does not crank, then your solenoid is bad or the starter is bad. You can test both components individually. If the test light does not light up on the signal wire when you turn the key, then it is probably your ignition switch or something leading to your ignition switch.

 

[Lancerdad34]

Then your battery switch should be good. The next steps would be what Bondo suggested. Clean all battery connections and look for corroded wires.

If that does not do it then put a test light on the signal wire on the starter solenoid like suggested. If it lights up and the engine does not crank, then your solenoid is bad or the starter is bad. You can test both components individually. If the test light does not light up on the signal wire when you turn the key, then it is probably your ignition switch or something leading to your ignition switch.

Thanks will try next time I have wife on boat to turn the key!

 

[Lancerdad34]

Then your battery switch should be good. The next steps would be what Bondo suggested. Clean all battery connections and look for corroded wires.

If that does not do it then put a test light on the signal wire on the starter solenoid like suggested. If it lights up and the engine does not crank, then your solenoid is bad or the starter is bad. You can test both components individually. If the test light does not light up on the signal wire when you turn the key, then it is probably your ignition switch or something leading to your ignition switch.

Well I took off the top of the air cleaner looking for the assist selonoid in case I ever have to jump it and did not find it it. I looked all over the top of the motor no selonoid or reset button. Any idea where it could be?

Thanks,
Brian

 

[Kola16]

We would need to know what engine you have (model/year or serial number, etc.). There are a lot of "5.0" engines. Or you could just follow the wires from the starter till you hit the solenoid.

 

[Lancerdad34]

We would need to know what engine you have (model/year or serial number, etc.). There are a lot of "5.0" engines. Or you could just follow the wires from the starter till you hit the solenoid.

It was a replacement engine in 2014. I will see if I can find that info
Thanks!
Brian

 

[alldodge]

What year is the boat?

 

[Lancerdad34]

What year is the boat?

Boat 2007 engine and outdrive 2014. I did find a number. OW667821.

 

[alldodge]

Your slave relay is not the typical one found on most, is the same as the fuel pump and main power relays. There are 3 of them and look for the one with the yellow/red wire on it, it will be the slave
https://www.mercruiserparts.com/bam/subassembly/31751/12840/40

 

[Lancerdad34]

Your slave relay is not the typical one found on most, is the same as the fuel pump and main power relays. There are 3 of them and look for the one with the yellow/red wire on it, it will be the slave
https://www.mercruiserparts.com/bam/subassembly/31751/12840/40

Thanks so much!

 

[Lancerdad34]

Your slave relay is not the typical one found on most, is the same as the fuel pump and main power relays. There are 3 of them and look for the one with the yellow/red wire on it, it will be the slave
https://www.mercruiserparts.com/bam/subassembly/31751/12840/40

When I click on it says trim relay. Are the trim and start relays the same?

 

[alldodge]

When I click on it says trim relay. Are the trim and start relays the same?

The start, main power and fuel pump ate all the same. The trim may be different and have not compared

 

[Lancerdad34]

The start, main power and fuel pump ate all the same. The trim may be different and have not compared

I have had no issues since this post in June until yesterday no crank when turning the key. I moved the batter switch to all then 1 and it started. Is it possible is could be the ignition switch? I did spray some contact cleaner in it. I tried 4 times in as row and it cranked. My question is also can a slave relay be intermittent like a slave solenoid? I have attached a photo just to make sure it is the right one.

Thanks,
Brian in MI

 

[alldodge]

Yes it could be the key switch, Pre 2000 use to last forever, new ones not so mush. Only 2 ways to know if it's bad, replace and see if it never does it again, or use a meter when it's not starting and measure voltages

 

[Lancerdad34]

Yes it could be the key switch, Pre 2000 use to last forever, new ones not so mush. Only 2 ways to know if it's bad, replace and see if it never does it again, or use a meter when it's not starting and measure voltages

Thanks for the reply! Just to be sure you said in a previous post that my engine does not have a slave solenoid. If it does I sure can't find it! I just want to confirm. Also can you recommend an ignition switch.

Thanks,

Brian in MI