Boat keeps cranking over

[tshaw84]

So this is the second time this has happened... First time I thought it was a bad solenoid...

It's in a Merc 350 with thunderbolt IV.

Replaced the solenoid the first time and the motor kept cranking over after I turned the key off.. Melted all my cables... Destroyed my battery Switch and melted the battery terminal off the battery...

New solenoid again... New battery and cables and it did it again! I've been on the boat a bunch of times since the first time... But now I am a bit nervous... I pulled the starter and just going to replace the entire thing this time... Anyone else ever have this happen?

 

[Bt Doctur]

Re: Boat keeps cranking over

what about the slave solenoid? ignition switch ?

 

[tshaw84]

Re: Boat keeps cranking over

Ignition switch seems in good shape... Haven't thought about the slave solenoid... Didn't think it would cause that.

 

[Bt Doctur]

Re: Boat keeps cranking over

power from the key energizes the slave, in turn energizes the main starter solenoid.

 

[tshaw84]

Re: Boat keeps cranking over

I will replace that too... I am going to replace starter too... That thing was so hot I couldn't touch it for 45 minutes... And still had to use gloves...

 

[dswi]

Re: Boat keeps cranking over

The starter can be rebuilt...or just cleaned out. I did mine last year and it never worked so good!

 

[frantically relaxing]

Re: Boat keeps cranking over

Ignition switches-- When we bought our SkipperLiner there were no ignition keys for the flybridge, so I bought a couple of new switches. Then it rained. BOTH ignition switches started the engines by themselves, on 2 separate nights. Brand new switches, a little water, and so much for switches "looking good"...

Now, THAT said, if your engines are cranking but not starting, it probably ISN'T the ignition switch, because the switch will energize the coil, and a sticking slave cylinder only energizes the starter...

 

[tshaw84]

Re: Boat keeps cranking over

My boat starts, but the PO unhooked the choke, so it takes a little bit...

but when I turn the key back to stop turning it over, it kept cranking...Wires melted, starter smoking...Battery post melting....

 

[tshaw84]

Re: Boat keeps cranking over

Here are pictures of my ugly mess...

 

[Bondo]

Re: Boat keeps cranking over

Ignition switches-- When we bought our SkipperLiner there were no ignition keys for the flybridge, so I bought a couple of new switches. Then it rained. BOTH ignition switches started the engines by themselves, on 2 separate nights. Brand new switches, a little water, and so much for switches "looking good"...

Now, THAT said, if your engines are cranking but not starting, it probably ISN'T the ignition switch, because the switch will energize the coil, and a sticking slave cylinder only energizes the starter...

Ayuh,.... 'n the Starter's solenoid powers the ignition durin' crankin',...

 

[tshaw84]

Re: Boat keeps cranking over

Both times it started cranking slow prior to sticking...

Who knows how old the starter is, but could a short or bad ground cause it?

Only reason I am thinking the starter is the culprit is because within the 30-45 seconds this happened, the starter could not be touched due to being so hot.

 

[Bondo]

Re: Boat keeps cranking over

Both times it started cranking slow prior to sticking...

Who knows how old the starter is, but could a short or bad ground cause it?

Only reason I am thinking the starter is the culprit is because within the 30-45 seconds this happened, the starter could not be touched due to being so hot.

Ayuh,.... That's plausible,... The solenoids sometimes hang up when the copper washer inside 'em gets carbon tracked,...

Low battery amperage can also cause it,...

 

[spdracr39]

Re: Boat keeps cranking over

Wow that thing was HOT !!!

 

[tshaw84]

Re: Boat keeps cranking over

I also saw another picture around here that had a 90a fuze off the starter? Without trying to sound like a total idiot....what is the purpose of that?

To avoid my issue? or to protect all your electronics? Both?

 

[Bondo]

Re: Boat keeps cranking over

I also saw another picture around here that had a 90a fuze off the starter? Without trying to sound like a total idiot....what is the purpose of that?

To avoid my issue? or to protect all your electronics? Both?

Ayuh,.... It was invented by Lawyers to prevent what happened to yer wirin', from bustin' into flames,...

Starter fuses are relatively a New thing,... didn't show up til shortly after the electronically controlled motors did,...

 

[tshaw84]

Re: Boat keeps cranking over

Alright, I have not seen them before. I am picking one of them up tonight as well.

So after tonight, with new start, slave solenoid, and fuse, hopefully these issues go away. I am just thankful I was in my driveway both times...

 

[tshaw84]

Re: Boat keeps cranking over

Put a new gear reduction starter in last night and boat cranks over and starts with no issues!