85' Mercruiser 5.0 won't crank...

[TampaBoater]

Ok brief story. A while ago my boat was making a single clicking sound when trying to start it. I replaced the slave solenoid like many suggested, and it worked, I got the motor running. Covered the boat for a week, when to go out today, and same problem, clicking sound and nothing. I knew it was not the slave again cause it's brand new, I thought starter solenoid or the started it self. Went and got a replacement and installed it. Now when I try to start, all I get is sort of a ratcheting sound, but no crank. Anyone has any idea what he cause of this is. I know the motor cannot be seized because I tool out the spark plugs and the motor turneb easily by hand, and I am in Tampa bay, no freezing temps here.
Please help.
Thanks,
Les.

 

[Bayou Dave]

Re: 85' Mercruiser 5.0 won't crank...

Have you checked for a weak battery, corroded battery cables ends, corroded cable ends on the starter?

 

[TampaBoater]

Re: 85' Mercruiser 5.0 won't crank...

Have you checked for a weak battery, corroded battery cables ends, corroded cable ends on the starter?

All wires are in good condition. Battery seems to be good.

 

[Bondo]

Re: 85' Mercruiser 5.0 won't crank...

All wires are in good condition.

Ayuh,... Did you remove the wire ends, 'n sand 'em Clean,..??

If not, you don't know the wirin' is "Good"....

 

[TampaBoater]

Re: 85' Mercruiser 5.0 won't crank...

Ayuh,... Did you remove the wire ends, 'n sand 'em Clean,..??

If not, you don't know the wirin' is "Good"....

I inspected them when I replaced the starter...

 

[Bondo]

Re: 85' Mercruiser 5.0 won't crank...

I inspected them when I replaced the starter...

And did you Sand 'em to CLEAN, SHINY metal,..??

Did you do the same to the Grounds,..??

Both ends of All the wires,..??

How 'bout the battery posts,..??

 

[TampaBoater]

Re: 85' Mercruiser 5.0 won't crank...

And did you Sand 'em to CLEAN, SHINY metal,..??

Did you do the same to the Grounds,..??

Both ends of All the wires,..??

No i did not.
I just now performed a voltage check at the slave solenoid, and when I turn the key, there is significant drop at the slave solenoid. Now I am not entirely sure what this means, I just thought I make note of it.

 

[MikDee]

Re: 85' Mercruiser 5.0 won't crank...

And did you Sand 'em to CLEAN, SHINY metal,..??

Did you do the same to the Grounds,..??

Both ends of All the wires,..??

How 'bout the battery posts,..??

I agree, this must be done once in awhile, that gray look maybe corrosion? They must be cleaned with a brush, or sandpaper till shiny. Then put some diaelectric grease on them, and tighten them up good. Now's the time to do it all, for peace of mind, and to eliminate future problems during the boating season.

 

[Maclin]

Re: 85' Mercruiser 5.0 won't crank...

The cable terminal ends may have wicked up some moisture and then corroded. Try to move the cable right at the terminal, should be pliable (check both ends on ALL cables, not just +). If it feels stiff until an inch or so back then the wire strands are probably corroded and acting like a resistor. The ends would need to be trimmed back and new terminal installed or new cable time.

 

[TampaBoater]

Re: 85' Mercruiser 5.0 won't crank...

The cable terminal ends may have wicked up some moisture and then corroded. Try to move the cable right at the terminal, should be pliable (check both ends on ALL cables, not just +). If it feels stiff until an inch or so back then the wire strands are probably corroded and acting like a resistor. The ends would need to be trimmed back and new terminal installed or new cable time.

So I took the battery to the store and it's at just over half of the rated cranking amps...we'll see after I get it back charged.

 

[Maclin]

Re: 85' Mercruiser 5.0 won't crank...

Many times a newly charged battery can overcome that resistance, just sayin', check the cable ends too because any resistance can affect charging as well :thumb:

 

[TampaBoater]

Re: 85' Mercruiser 5.0 won't crank...

Many times a newly charged battery can overcome that resistance, just sayin', check the cable ends too because any resistance can affect charging as well :thumb:

Well, back to the same issue, fully charged battery and still just get the ratcheting sound from the starter (New) but no crank.
Don't know what else to do now.

 

[Bondo]

Re: 85' Mercruiser 5.0 won't crank...

Well, back to the same issue, fully charged battery and still just get the ratcheting sound from the starter (New) but no crank.
Don't know what else to do now.

Ayuh,.... Did ya CLEAN THE WIRIN" ENDS,..??..??

 

[TampaBoater]

Re: 85' Mercruiser 5.0 won't crank...

Ayuh,.... Did ya CLEAN THE WIRIN" ENDS,..??..??

No but I got it started. I connected the black wire coming from the gear plate assembly, to the other small post on the slave solenoid. I turn the key, and the started engaged by the wire smoked up a bit. I disconnected it, and then turned the key again, and lo and behold it starts. Crazy *** boat.

 

[Bondo]

Re: 85' Mercruiser 5.0 won't crank...

No but I got it started. I connected the black wire coming from the gear plate assembly, to the other small post on the slave solenoid. I turn the key, and the started engaged by the wire smoked up a bit. I disconnected it, and then turned the key again, and lo and behold it starts. Crazy *** boat.

Ayuh,.... That, is the definition of Bad wirin' connections,... Corrosion,...

Nothin' Crazy 'bout the boat,...

 

[Haut Medoc]

Re: 85' Mercruiser 5.0 won't crank...

Don't consider it fixed or you will pay for it on the water once....
Heat = Resistance
Clean the terminals as Bondo suggests...
Isolate the problem by testing wires one at time......
A jumper from the key switch to the solenoid will tell you if there is a problem there, & so on...
My guess is the main cable from the solenoid to the starter has a problem, IE internal corrosion...
This should be easy to isolate if you take a methodical approach...

 

[MikDee]

Re: 85' Mercruiser 5.0 won't crank...

I turn the key, and the started engaged by the wire smoked up a bit. I disconnected it, and then turned the key again, and lo and behold it starts. Crazy *** boat.

The issue is still there then! Sometimes you can't notice corrosion, until you remove it,,, Clean the battery terminals! like Bondo said